diff --git a/bindings/pylibafl/src/lib.rs b/bindings/pylibafl/src/lib.rs
index 2bb8f11e2c..914fca662b 100644
--- a/bindings/pylibafl/src/lib.rs
+++ b/bindings/pylibafl/src/lib.rs
@@ -46,9 +46,9 @@ class BaseStage:
         return Stage.new_py(self)
 
 class BaseMutator:
-    def mutate(self, state, input, stage_idx):
+    def mutate(self, state, input):
         pass
-    def post_exec(self, state, stage_idx, corpus_idx):
+    def post_exec(self, state, corpus_idx):
         pass
     def as_mutator(self):
         return Mutator.new_py(self)
diff --git a/fuzzers/push_stage_harness/src/main.rs b/fuzzers/push_stage_harness/src/main.rs
index 201a3a860c..27c78c26ef 100644
--- a/fuzzers/push_stage_harness/src/main.rs
+++ b/fuzzers/push_stage_harness/src/main.rs
@@ -31,10 +31,11 @@ fn signals_set(idx: usize) {
     unsafe { SIGNALS[idx] = 1 };
 }
 
-#[allow(clippy::similar_names)]
+#[allow(clippy::similar_names, clippy::manual_assert)]
 pub fn main() {
     // Create an observation channel using the signals map
-    let observer = unsafe { StdMapObserver::new("signals", &mut SIGNALS) };
+    let observer =
+        unsafe { StdMapObserver::from_mut_ptr("signals", SIGNALS.as_mut_ptr(), SIGNALS.len()) };
 
     // Feedback to rate the interestingness of an input
     let mut feedback = MaxMapFeedback::new(&observer);
@@ -90,8 +91,6 @@ pub fn main() {
 
     let exit_kind = Rc::new(Cell::new(None));
 
-    let stage_idx = 0;
-
     let observers = tuple_list!(observer);
 
     let shared_state = PushStageSharedState::new(fuzzer, state, observers, mgr);
@@ -101,7 +100,6 @@ pub fn main() {
         mutator,
         Rc::new(RefCell::new(Some(shared_state))),
         exit_kind.clone(),
-        stage_idx,
     );
 
     // Loop, the input, getting a new entry from the push stage each iteration.
diff --git a/fuzzers/tutorial/src/mutator.rs b/fuzzers/tutorial/src/mutator.rs
index ce9d85ad51..09ebbb3454 100644
--- a/fuzzers/tutorial/src/mutator.rs
+++ b/fuzzers/tutorial/src/mutator.rs
@@ -19,12 +19,7 @@ impl<S> Mutator<PacketData, S> for LainMutator
 where
     S: HasRand,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut PacketData,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut PacketData) -> Result<MutationResult, Error> {
         // Lain uses its own instance of StdRand, but we want to keep it in sync with LibAFL's state.
         self.inner.rng_mut().set_seed(state.rand_mut().next());
         input.mutate(&mut self.inner, None);
diff --git a/libafl/src/mutators/encoded_mutations.rs b/libafl/src/mutators/encoded_mutations.rs
index 3c5b9215f0..9a29945bff 100644
--- a/libafl/src/mutators/encoded_mutations.rs
+++ b/libafl/src/mutators/encoded_mutations.rs
@@ -25,12 +25,7 @@ use crate::{
 pub struct EncodedRandMutator;
 
 impl<S: HasRand> Mutator<EncodedInput, S> for EncodedRandMutator {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut EncodedInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut EncodedInput) -> Result<MutationResult, Error> {
         if input.codes().is_empty() {
             Ok(MutationResult::Skipped)
         } else {
@@ -60,12 +55,7 @@ impl EncodedRandMutator {
 pub struct EncodedIncMutator;
 
 impl<S: HasRand> Mutator<EncodedInput, S> for EncodedIncMutator {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut EncodedInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut EncodedInput) -> Result<MutationResult, Error> {
         if input.codes().is_empty() {
             Ok(MutationResult::Skipped)
         } else {
@@ -95,12 +85,7 @@ impl EncodedIncMutator {
 pub struct EncodedDecMutator;
 
 impl<S: HasRand> Mutator<EncodedInput, S> for EncodedDecMutator {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut EncodedInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut EncodedInput) -> Result<MutationResult, Error> {
         if input.codes().is_empty() {
             Ok(MutationResult::Skipped)
         } else {
@@ -130,12 +115,7 @@ impl EncodedDecMutator {
 pub struct EncodedAddMutator;
 
 impl<S: HasRand> Mutator<EncodedInput, S> for EncodedAddMutator {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut EncodedInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut EncodedInput) -> Result<MutationResult, Error> {
         if input.codes().is_empty() {
             Ok(MutationResult::Skipped)
         } else {
@@ -169,12 +149,7 @@ impl EncodedAddMutator {
 pub struct EncodedDeleteMutator;
 
 impl<S: HasRand> Mutator<EncodedInput, S> for EncodedDeleteMutator {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut EncodedInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut EncodedInput) -> Result<MutationResult, Error> {
         let size = input.codes().len();
         if size <= 2 {
             return Ok(MutationResult::Skipped);
@@ -212,12 +187,7 @@ impl<S> Mutator<EncodedInput, S> for EncodedInsertCopyMutator
 where
     S: HasRand + HasMaxSize,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut EncodedInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut EncodedInput) -> Result<MutationResult, Error> {
         let max_size = state.max_size();
         let size = input.codes().len();
         if size == 0 {
@@ -272,12 +242,7 @@ impl EncodedInsertCopyMutator {
 pub struct EncodedCopyMutator;
 
 impl<S: HasRand> Mutator<EncodedInput, S> for EncodedCopyMutator {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut EncodedInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut EncodedInput) -> Result<MutationResult, Error> {
         let size = input.codes().len();
         if size <= 1 {
             return Ok(MutationResult::Skipped);
@@ -317,12 +282,7 @@ impl<S> Mutator<S::Input, S> for EncodedCrossoverInsertMutator
 where
     S: UsesInput<Input = EncodedInput> + HasRand + HasCorpus + HasMaxSize,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut EncodedInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut EncodedInput) -> Result<MutationResult, Error> {
         let size = input.codes().len();
 
         // We don't want to use the testcase we're already using for splicing
@@ -391,12 +351,7 @@ impl<S> Mutator<S::Input, S> for EncodedCrossoverReplaceMutator
 where
     S: UsesInput<Input = EncodedInput> + HasRand + HasCorpus,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut EncodedInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut EncodedInput) -> Result<MutationResult, Error> {
         let size = input.codes().len();
         if size == 0 {
             return Ok(MutationResult::Skipped);
diff --git a/libafl/src/mutators/gramatron.rs b/libafl/src/mutators/gramatron.rs
index 231523b3e7..6deee6f93b 100644
--- a/libafl/src/mutators/gramatron.rs
+++ b/libafl/src/mutators/gramatron.rs
@@ -36,7 +36,6 @@ where
         &mut self,
         state: &mut S,
         input: &mut GramatronInput,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         if !input.terminals().is_empty() {
             let size = state.rand_mut().below(input.terminals().len() as u64 + 1) as usize;
@@ -109,7 +108,6 @@ where
         &mut self,
         state: &mut S,
         input: &mut GramatronInput,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         if input.terminals().is_empty() {
             return Ok(MutationResult::Skipped);
@@ -180,7 +178,6 @@ where
         &mut self,
         state: &mut S,
         input: &mut GramatronInput,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         if input.terminals().is_empty() {
             return Ok(MutationResult::Skipped);
diff --git a/libafl/src/mutators/grimoire.rs b/libafl/src/mutators/grimoire.rs
index c115b9db4d..49dba54a5c 100644
--- a/libafl/src/mutators/grimoire.rs
+++ b/libafl/src/mutators/grimoire.rs
@@ -122,7 +122,6 @@ where
         &mut self,
         state: &mut S,
         generalised_meta: &mut GeneralizedInputMetadata,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         extend_with_random_generalized(
             state,
@@ -163,7 +162,6 @@ where
         &mut self,
         state: &mut S,
         generalised_meta: &mut GeneralizedInputMetadata,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         let mut mutated = MutationResult::Skipped;
 
@@ -236,7 +234,6 @@ where
         &mut self,
         state: &mut S,
         generalised_meta: &mut GeneralizedInputMetadata,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         let tokens_len = {
             let meta = state.metadata_map().get::<Tokens>();
@@ -347,7 +344,6 @@ where
         &mut self,
         state: &mut S,
         generalised_meta: &mut GeneralizedInputMetadata,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         let gen = generalised_meta.generalized_mut();
 
diff --git a/libafl/src/mutators/mod.rs b/libafl/src/mutators/mod.rs
index 80ddb2207a..6828f5fbf7 100644
--- a/libafl/src/mutators/mod.rs
+++ b/libafl/src/mutators/mod.rs
@@ -91,12 +91,7 @@ pub enum MutationResult {
 /// Simple as that.
 pub trait Mutator<I, S>: Named {
     /// Mutate a given input
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error>;
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error>;
 
     /// Post-process given the outcome of the execution
     /// `new_corpus_idx` will be `Some` if a new `Testcase` was created this execution.
@@ -104,7 +99,6 @@ pub trait Mutator<I, S>: Named {
     fn post_exec(
         &mut self,
         _state: &mut S,
-        _stage_idx: i32,
         _new_corpus_idx: Option<CorpusId>,
     ) -> Result<(), Error> {
         Ok(())
@@ -120,7 +114,6 @@ pub trait MultiMutator<I, S>: Named {
         &mut self,
         state: &mut S,
         input: &I,
-        stage_idx: i32,
         max_count: Option<usize>,
     ) -> Result<Vec<I>, Error>;
 
@@ -130,7 +123,6 @@ pub trait MultiMutator<I, S>: Named {
     fn multi_post_exec(
         &mut self,
         _state: &mut S,
-        _stage_idx: i32,
         _new_corpus_idx: Option<CorpusId>,
     ) -> Result<(), Error> {
         Ok(())
@@ -140,19 +132,13 @@ pub trait MultiMutator<I, S>: Named {
 /// A `Tuple` of `Mutators` that can execute multiple `Mutators` in a row.
 pub trait MutatorsTuple<I, S>: HasLen {
     /// Runs the `mutate` function on all `Mutators` in this `Tuple`.
-    fn mutate_all(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error>;
+    fn mutate_all(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error>;
 
     /// Runs the `post_exec` function on all `Mutators` in this `Tuple`.
     /// `new_corpus_idx` will be `Some` if a new `Testcase` was created this execution.
     fn post_exec_all(
         &mut self,
         state: &mut S,
-        stage_idx: i32,
         new_corpus_idx: Option<CorpusId>,
     ) -> Result<(), Error>;
 
@@ -162,7 +148,6 @@ pub trait MutatorsTuple<I, S>: HasLen {
         index: MutationId,
         state: &mut S,
         input: &mut I,
-        stage_idx: i32,
     ) -> Result<MutationResult, Error>;
 
     /// Gets the [`Mutator`] at the given index and runs the `post_exec` function on it.
@@ -171,7 +156,7 @@ pub trait MutatorsTuple<I, S>: HasLen {
         &mut self,
         index: usize,
         state: &mut S,
-        stage_idx: i32,
+
         corpus_idx: Option<CorpusId>,
     ) -> Result<(), Error>;
 
@@ -184,12 +169,7 @@ pub trait MutatorsTuple<I, S>: HasLen {
 
 impl<I, S> MutatorsTuple<I, S> for () {
     #[inline]
-    fn mutate_all(
-        &mut self,
-        _state: &mut S,
-        _input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate_all(&mut self, _state: &mut S, _input: &mut I) -> Result<MutationResult, Error> {
         Ok(MutationResult::Skipped)
     }
 
@@ -197,7 +177,6 @@ impl<I, S> MutatorsTuple<I, S> for () {
     fn post_exec_all(
         &mut self,
         _state: &mut S,
-        _stage_idx: i32,
         _new_corpus_idx: Option<CorpusId>,
     ) -> Result<(), Error> {
         Ok(())
@@ -209,7 +188,6 @@ impl<I, S> MutatorsTuple<I, S> for () {
         _index: MutationId,
         _state: &mut S,
         _input: &mut I,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         Ok(MutationResult::Skipped)
     }
@@ -219,7 +197,6 @@ impl<I, S> MutatorsTuple<I, S> for () {
         &mut self,
         _index: usize,
         _state: &mut S,
-        _stage_idx: i32,
         _new_corpus_idx: Option<CorpusId>,
     ) -> Result<(), Error> {
         Ok(())
@@ -241,14 +218,9 @@ where
     Head: Mutator<I, S>,
     Tail: MutatorsTuple<I, S>,
 {
-    fn mutate_all(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
-        let r = self.0.mutate(state, input, stage_idx)?;
-        if self.1.mutate_all(state, input, stage_idx)? == MutationResult::Mutated {
+    fn mutate_all(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
+        let r = self.0.mutate(state, input)?;
+        if self.1.mutate_all(state, input)? == MutationResult::Mutated {
             Ok(MutationResult::Mutated)
         } else {
             Ok(r)
@@ -258,11 +230,10 @@ where
     fn post_exec_all(
         &mut self,
         state: &mut S,
-        stage_idx: i32,
         new_corpus_idx: Option<CorpusId>,
     ) -> Result<(), Error> {
-        self.0.post_exec(state, stage_idx, new_corpus_idx)?;
-        self.1.post_exec_all(state, stage_idx, new_corpus_idx)
+        self.0.post_exec(state, new_corpus_idx)?;
+        self.1.post_exec_all(state, new_corpus_idx)
     }
 
     fn get_and_mutate(
@@ -270,13 +241,11 @@ where
         index: MutationId,
         state: &mut S,
         input: &mut I,
-        stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         if index.0 == 0 {
-            self.0.mutate(state, input, stage_idx)
+            self.0.mutate(state, input)
         } else {
-            self.1
-                .get_and_mutate((index.0 - 1).into(), state, input, stage_idx)
+            self.1.get_and_mutate((index.0 - 1).into(), state, input)
         }
     }
 
@@ -284,14 +253,12 @@ where
         &mut self,
         index: usize,
         state: &mut S,
-        stage_idx: i32,
         new_corpus_idx: Option<CorpusId>,
     ) -> Result<(), Error> {
         if index == 0 {
-            self.0.post_exec(state, stage_idx, new_corpus_idx)
+            self.0.post_exec(state, new_corpus_idx)
         } else {
-            self.1
-                .get_and_post_exec(index - 1, state, stage_idx, new_corpus_idx)
+            self.1.get_and_post_exec(index - 1, state, new_corpus_idx)
         }
     }
 
@@ -331,22 +298,16 @@ impl<Tail, I, S> MutatorsTuple<I, S> for (Tail,)
 where
     Tail: MutatorsTuple<I, S>,
 {
-    fn mutate_all(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
-        self.0.mutate_all(state, input, stage_idx)
+    fn mutate_all(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
+        self.0.mutate_all(state, input)
     }
 
     fn post_exec_all(
         &mut self,
         state: &mut S,
-        stage_idx: i32,
         new_corpus_idx: Option<CorpusId>,
     ) -> Result<(), Error> {
-        self.0.post_exec_all(state, stage_idx, new_corpus_idx)
+        self.0.post_exec_all(state, new_corpus_idx)
     }
 
     fn get_and_mutate(
@@ -354,20 +315,17 @@ where
         index: MutationId,
         state: &mut S,
         input: &mut I,
-        stage_idx: i32,
     ) -> Result<MutationResult, Error> {
-        self.0.get_and_mutate(index, state, input, stage_idx)
+        self.0.get_and_mutate(index, state, input)
     }
 
     fn get_and_post_exec(
         &mut self,
         index: usize,
         state: &mut S,
-        stage_idx: i32,
         new_corpus_idx: Option<CorpusId>,
     ) -> Result<(), Error> {
-        self.0
-            .get_and_post_exec(index, state, stage_idx, new_corpus_idx)
+        self.0.get_and_post_exec(index, state, new_corpus_idx)
     }
 
     fn names(&self) -> Vec<&str> {
@@ -389,15 +347,10 @@ where
 }
 
 impl<I, S> MutatorsTuple<I, S> for Vec<Box<dyn Mutator<I, S>>> {
-    fn mutate_all(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate_all(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         self.iter_mut()
             .try_fold(MutationResult::Skipped, |ret, mutator| {
-                if mutator.mutate(state, input, stage_idx)? == MutationResult::Mutated {
+                if mutator.mutate(state, input)? == MutationResult::Mutated {
                     Ok(MutationResult::Mutated)
                 } else {
                     Ok(ret)
@@ -408,11 +361,10 @@ impl<I, S> MutatorsTuple<I, S> for Vec<Box<dyn Mutator<I, S>>> {
     fn post_exec_all(
         &mut self,
         state: &mut S,
-        stage_idx: i32,
         new_corpus_idx: Option<CorpusId>,
     ) -> Result<(), Error> {
         for mutator in self.iter_mut() {
-            mutator.post_exec(state, stage_idx, new_corpus_idx)?;
+            mutator.post_exec(state, new_corpus_idx)?;
         }
         Ok(())
     }
@@ -422,25 +374,23 @@ impl<I, S> MutatorsTuple<I, S> for Vec<Box<dyn Mutator<I, S>>> {
         index: MutationId,
         state: &mut S,
         input: &mut I,
-        stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         let mutator = self
             .get_mut(index.0)
             .ok_or_else(|| Error::key_not_found("Mutator with id {index:?} not found."))?;
-        mutator.mutate(state, input, stage_idx)
+        mutator.mutate(state, input)
     }
 
     fn get_and_post_exec(
         &mut self,
         index: usize,
         state: &mut S,
-        stage_idx: i32,
         new_corpus_idx: Option<CorpusId>,
     ) -> Result<(), Error> {
         let mutator = self
             .get_mut(index)
             .ok_or_else(|| Error::key_not_found("Mutator with id {index:?} not found."))?;
-        mutator.post_exec(state, stage_idx, new_corpus_idx)
+        mutator.post_exec(state, new_corpus_idx)
     }
 
     fn names_reversed(&self) -> Vec<&str> {
@@ -501,14 +451,13 @@ pub mod pybind {
             &mut self,
             state: &mut PythonStdState,
             input: &mut BytesInput,
-            stage_idx: i32,
         ) -> Result<MutationResult, Error> {
             let mutated = Python::with_gil(|py| -> PyResult<bool> {
                 self.inner
                     .call_method1(
                         py,
                         "mutate",
-                        (PythonStdStateWrapper::wrap(state), input.bytes(), stage_idx),
+                        (PythonStdStateWrapper::wrap(state), input.bytes()),
                     )?
                     .extract(py)
             })?;
@@ -522,18 +471,14 @@ pub mod pybind {
         fn post_exec(
             &mut self,
             state: &mut PythonStdState,
-            stage_idx: i32,
+
             corpus_idx: Option<CorpusId>,
         ) -> Result<(), Error> {
             Python::with_gil(|py| -> PyResult<()> {
                 self.inner.call_method1(
                     py,
                     "post_exec",
-                    (
-                        PythonStdStateWrapper::wrap(state),
-                        stage_idx,
-                        corpus_idx.map(|x| x.0),
-                    ),
+                    (PythonStdStateWrapper::wrap(state), corpus_idx.map(|x| x.0)),
                 )?;
                 Ok(())
             })?;
@@ -609,20 +554,17 @@ pub mod pybind {
             &mut self,
             state: &mut PythonStdState,
             input: &mut BytesInput,
-            stage_idx: i32,
         ) -> Result<MutationResult, Error> {
-            unwrap_me_mut!(self.wrapper, m, { m.mutate(state, input, stage_idx) })
+            unwrap_me_mut!(self.wrapper, m, { m.mutate(state, input) })
         }
 
         fn post_exec(
             &mut self,
             state: &mut PythonStdState,
-            stage_idx: i32,
+
             corpus_idx: Option<CorpusId>,
         ) -> Result<(), Error> {
-            unwrap_me_mut!(self.wrapper, m, {
-                m.post_exec(state, stage_idx, corpus_idx)
-            })
+            unwrap_me_mut!(self.wrapper, m, { m.post_exec(state, corpus_idx) })
         }
     }
 
diff --git a/libafl/src/mutators/mopt_mutator.rs b/libafl/src/mutators/mopt_mutator.rs
index 348269cead..143aaed82b 100644
--- a/libafl/src/mutators/mopt_mutator.rs
+++ b/libafl/src/mutators/mopt_mutator.rs
@@ -404,23 +404,13 @@ where
     S: HasRand + HasMetadata + HasCorpus + HasSolutions,
 {
     #[inline]
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         self.finds_before = state.corpus().count() + state.solutions().count();
-        self.scheduled_mutate(state, input, stage_idx)
+        self.scheduled_mutate(state, input)
     }
 
     #[allow(clippy::cast_precision_loss)]
-    fn post_exec(
-        &mut self,
-        state: &mut S,
-        _stage_idx: i32,
-        _new_corpus_idx: Option<CorpusId>,
-    ) -> Result<(), Error> {
+    fn post_exec(&mut self, state: &mut S, _new_corpus_idx: Option<CorpusId>) -> Result<(), Error> {
         let before = self.finds_before;
         let after = state.corpus().count() + state.solutions().count();
 
@@ -558,12 +548,7 @@ where
             phantom: PhantomData,
         })
     }
-    fn core_mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn core_mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let mut r = MutationResult::Skipped;
         let mopt = state.metadata_map_mut().get_mut::<MOpt>().unwrap();
         for i in 0..mopt.operator_num {
@@ -572,9 +557,7 @@ where
 
         for _i in 0..self.iterations(state, input) {
             let idx = self.schedule(state, input);
-            let outcome = self
-                .mutations_mut()
-                .get_and_mutate(idx, state, input, stage_idx)?;
+            let outcome = self.mutations_mut().get_and_mutate(idx, state, input)?;
             if outcome == MutationResult::Mutated {
                 r = MutationResult::Mutated;
             }
@@ -588,12 +571,7 @@ where
         Ok(r)
     }
 
-    fn pilot_mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn pilot_mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let mut r = MutationResult::Skipped;
         let swarm_now;
         {
@@ -608,9 +586,7 @@ where
 
         for _i in 0..self.iterations(state, input) {
             let idx = self.schedule(state, input);
-            let outcome = self
-                .mutations_mut()
-                .get_and_mutate(idx, state, input, stage_idx)?;
+            let outcome = self.mutations_mut().get_and_mutate(idx, state, input)?;
             if outcome == MutationResult::Mutated {
                 r = MutationResult::Mutated;
             }
@@ -675,16 +651,11 @@ where
             .unwrap()
     }
 
-    fn scheduled_mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn scheduled_mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let mode = self.mode;
         match mode {
-            MOptMode::Corefuzzing => self.core_mutate(state, input, stage_idx),
-            MOptMode::Pilotfuzzing => self.pilot_mutate(state, input, stage_idx),
+            MOptMode::Corefuzzing => self.core_mutate(state, input),
+            MOptMode::Pilotfuzzing => self.pilot_mutate(state, input),
         }
     }
 }
diff --git a/libafl/src/mutators/multi.rs b/libafl/src/mutators/multi.rs
index b6a9847cdb..05ceccf969 100644
--- a/libafl/src/mutators/multi.rs
+++ b/libafl/src/mutators/multi.rs
@@ -40,24 +40,18 @@ where
         &mut self,
         state: &mut S,
         input: &mut MultipartInput<I>,
-        stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         if input.parts().is_empty() {
             Ok(MutationResult::Skipped)
         } else {
             let selected = state.rand_mut().below(input.parts().len() as u64) as usize;
             let mutated = input.part_mut(selected).unwrap();
-            self.mutate(state, mutated, stage_idx)
+            self.mutate(state, mutated)
         }
     }
 
-    fn post_exec(
-        &mut self,
-        state: &mut S,
-        stage_idx: i32,
-        new_corpus_idx: Option<CorpusId>,
-    ) -> Result<(), Error> {
-        M::post_exec(self, state, stage_idx, new_corpus_idx)
+    fn post_exec(&mut self, state: &mut S, new_corpus_idx: Option<CorpusId>) -> Result<(), Error> {
+        M::post_exec(self, state, new_corpus_idx)
     }
 }
 
@@ -129,7 +123,6 @@ where
         &mut self,
         state: &mut S,
         input: &mut MultipartInput<I>,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         // we can eat the slight bias; number of parts will be small
         let name_choice = state.rand_mut().next() as usize;
@@ -234,7 +227,6 @@ where
         &mut self,
         state: &mut S,
         input: &mut MultipartInput<I>,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         // we can eat the slight bias; number of parts will be small
         let name_choice = state.rand_mut().next() as usize;
diff --git a/libafl/src/mutators/mutations.rs b/libafl/src/mutators/mutations.rs
index f979ab81e0..c0d57f5e21 100644
--- a/libafl/src/mutators/mutations.rs
+++ b/libafl/src/mutators/mutations.rs
@@ -122,12 +122,7 @@ where
     S: HasRand,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         if input.bytes().is_empty() {
             Ok(MutationResult::Skipped)
         } else {
@@ -162,12 +157,7 @@ where
     S: HasRand,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         if input.bytes().is_empty() {
             Ok(MutationResult::Skipped)
         } else {
@@ -200,12 +190,7 @@ where
     S: HasRand,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         if input.bytes().is_empty() {
             Ok(MutationResult::Skipped)
         } else {
@@ -239,12 +224,7 @@ where
     S: HasRand,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         if input.bytes().is_empty() {
             Ok(MutationResult::Skipped)
         } else {
@@ -278,12 +258,7 @@ where
     S: HasRand,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         if input.bytes().is_empty() {
             Ok(MutationResult::Skipped)
         } else {
@@ -317,12 +292,7 @@ where
     S: HasRand,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         if input.bytes().is_empty() {
             Ok(MutationResult::Skipped)
         } else {
@@ -365,7 +335,7 @@ macro_rules! add_mutator_impl {
                 &mut self,
                 state: &mut S,
                 input: &mut I,
-                _stage_idx: i32,
+
             ) -> Result<MutationResult, Error> {
                 if input.bytes().len() < size_of::<$size>() {
                     Ok(MutationResult::Skipped)
@@ -428,12 +398,7 @@ macro_rules! interesting_mutator_impl {
             I: HasBytesVec,
         {
             #[allow(clippy::cast_sign_loss)]
-            fn mutate(
-                &mut self,
-                state: &mut S,
-                input: &mut I,
-                _stage_idx: i32,
-            ) -> Result<MutationResult, Error> {
+            fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
                 if input.bytes().len() < size_of::<$size>() {
                     Ok(MutationResult::Skipped)
                 } else {
@@ -480,12 +445,7 @@ where
     S: HasRand,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let size = input.bytes().len();
         if size <= 2 {
             return Ok(MutationResult::Skipped);
@@ -522,12 +482,7 @@ where
     S: HasRand + HasMaxSize,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let max_size = state.max_size();
         let size = input.bytes().len();
         if size == 0 || size >= max_size {
@@ -573,12 +528,7 @@ where
     S: HasRand + HasMaxSize,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let max_size = state.max_size();
         let size = input.bytes().len();
         if size == 0 || size >= max_size {
@@ -631,12 +581,7 @@ where
     S: HasRand + HasMaxSize,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let max_size = state.max_size();
         let size = input.bytes().len();
         if size >= max_size {
@@ -689,12 +634,7 @@ where
     S: HasRand,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let size = input.bytes().len();
         if size == 0 {
             return Ok(MutationResult::Skipped);
@@ -732,12 +672,7 @@ where
     S: HasRand,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let size = input.bytes().len();
         if size == 0 {
             return Ok(MutationResult::Skipped);
@@ -775,12 +710,7 @@ where
     S: HasRand,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let size = input.bytes().len();
         if size <= 1 {
             return Ok(MutationResult::Skipped);
@@ -822,12 +752,7 @@ where
     S: HasRand + HasMaxSize,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let size = input.bytes().len();
         if size <= 1 || size >= state.max_size() {
             return Ok(MutationResult::Skipped);
@@ -887,12 +812,7 @@ where
     S: HasRand,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let size = input.bytes().len();
         if size <= 1 {
             return Ok(MutationResult::Skipped);
@@ -1125,12 +1045,7 @@ where
     S: HasCorpus<Input = I> + HasRand + HasMaxSize,
     I: Input + HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut S::Input,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut S::Input) -> Result<MutationResult, Error> {
         let size = input.bytes().len();
         let max_size = state.max_size();
         if size >= max_size {
@@ -1213,12 +1128,7 @@ where
     S: HasCorpus<Input = I> + HasRand,
     I: Input + HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut S::Input,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut S::Input) -> Result<MutationResult, Error> {
         let size = input.bytes().len();
         if size == 0 {
             return Ok(MutationResult::Skipped);
@@ -1295,12 +1205,7 @@ where
     S::Input: HasBytesVec,
 {
     #[allow(clippy::cast_sign_loss)]
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut S::Input,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut S::Input) -> Result<MutationResult, Error> {
         // We don't want to use the testcase we're already using for splicing
         let idx = random_corpus_id!(state.corpus(), state.rand_mut());
         if let Some(cur) = state.corpus().current() {
@@ -1508,7 +1413,7 @@ mod tests {
                 for input in &inputs {
                     let mut mutant = input.clone();
                     match mutations
-                        .get_and_mutate(idx.into(), &mut state, &mut mutant, 0)
+                        .get_and_mutate(idx.into(), &mut state, &mut mutant)
                         .unwrap()
                     {
                         MutationResult::Mutated => new_testcases.push(mutant),
@@ -1534,7 +1439,7 @@ mod tests {
 
         for _ in 0..iters {
             let mut mutated = base.clone();
-            if mutator.mutate(&mut state, &mut mutated, 0)? == MutationResult::Skipped {
+            if mutator.mutate(&mut state, &mut mutated)? == MutationResult::Skipped {
                 continue;
             }
             let mut gaps = 0;
@@ -1588,7 +1493,7 @@ mod tests {
 
         for _ in 0..iters {
             let mut mutated = base.clone();
-            if mutator.mutate(&mut state, &mut mutated, 0)? == MutationResult::Skipped {
+            if mutator.mutate(&mut state, &mut mutated)? == MutationResult::Skipped {
                 continue;
             }
             let mut expansion = 0;
@@ -1637,7 +1542,7 @@ mod tests {
 
         for _ in 0..iters {
             let mut mutated = base.clone();
-            if mutator.mutate(&mut state, &mut mutated, 0)? == MutationResult::Skipped {
+            if mutator.mutate(&mut state, &mut mutated)? == MutationResult::Skipped {
                 continue;
             }
             let mut inserted = 0;
@@ -1687,7 +1592,7 @@ mod tests {
 
         for _ in 0..iters {
             let mut mutated = base.clone();
-            if mutator.mutate(&mut state, &mut mutated, 0)? == MutationResult::Skipped {
+            if mutator.mutate(&mut state, &mut mutated)? == MutationResult::Skipped {
                 continue;
             }
             let mut inserted = 10;
diff --git a/libafl/src/mutators/nautilus.rs b/libafl/src/mutators/nautilus.rs
index d6b64808f9..7637dec32b 100644
--- a/libafl/src/mutators/nautilus.rs
+++ b/libafl/src/mutators/nautilus.rs
@@ -35,7 +35,6 @@ impl<S> Mutator<NautilusInput, S> for NautilusRandomMutator<'_> {
         &mut self,
         _state: &mut S,
         input: &mut NautilusInput,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         // TODO get rid of tmp
         let mut tmp = vec![];
@@ -96,7 +95,6 @@ impl<S> Mutator<NautilusInput, S> for NautilusRecursionMutator<'_> {
         &mut self,
         _state: &mut S,
         input: &mut NautilusInput,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         // TODO don't calc recursions here
         if let Some(ref mut recursions) = input.tree.calc_recursions(self.ctx) {
@@ -162,7 +160,6 @@ where
         &mut self,
         state: &mut S,
         input: &mut NautilusInput,
-        _stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         let meta = state
             .metadata_map()
diff --git a/libafl/src/mutators/scheduled.rs b/libafl/src/mutators/scheduled.rs
index a862a2a55e..eeee1b94b1 100644
--- a/libafl/src/mutators/scheduled.rs
+++ b/libafl/src/mutators/scheduled.rs
@@ -93,19 +93,12 @@ where
 
     /// New default implementation for mutate.
     /// Implementations must forward `mutate()` to this method
-    fn scheduled_mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn scheduled_mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let mut r = MutationResult::Skipped;
         let num = self.iterations(state, input);
         for _ in 0..num {
             let idx = self.schedule(state, input);
-            let outcome = self
-                .mutations_mut()
-                .get_and_mutate(idx, state, input, stage_idx)?;
+            let outcome = self.mutations_mut().get_and_mutate(idx, state, input)?;
             if outcome == MutationResult::Mutated {
                 r = MutationResult::Mutated;
             }
@@ -157,13 +150,8 @@ where
     S: HasRand,
 {
     #[inline]
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
-        self.scheduled_mutate(state, input, stage_idx)
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
+        self.scheduled_mutate(state, input)
     }
 }
 
@@ -391,21 +379,11 @@ where
     S: HasRand + HasCorpus,
     SM: ScheduledMutator<I, MT, S>,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
-        self.scheduled_mutate(state, input, stage_idx)
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
+        self.scheduled_mutate(state, input)
     }
 
-    fn post_exec(
-        &mut self,
-        state: &mut S,
-        _stage_idx: i32,
-        corpus_idx: Option<CorpusId>,
-    ) -> Result<(), Error> {
+    fn post_exec(&mut self, state: &mut S, corpus_idx: Option<CorpusId>) -> Result<(), Error> {
         if let Some(idx) = corpus_idx {
             let mut testcase = (*state.corpus_mut().get(idx)?).borrow_mut();
             let mut log = Vec::<String>::new();
@@ -456,21 +434,14 @@ where
         state.rand_mut().below(MT::LEN as u64).into()
     }
 
-    fn scheduled_mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn scheduled_mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let mut r = MutationResult::Skipped;
         let num = self.iterations(state, input);
         self.mutation_log.clear();
         for _ in 0..num {
             let idx = self.schedule(state, input);
             self.mutation_log.push(idx);
-            let outcome = self
-                .mutations_mut()
-                .get_and_mutate(idx, state, input, stage_idx)?;
+            let outcome = self.mutations_mut().get_and_mutate(idx, state, input)?;
             if outcome == MutationResult::Mutated {
                 r = MutationResult::Mutated;
             }
@@ -542,7 +513,7 @@ mod tests {
         rand.set_seed(5);
 
         let mut splice = SpliceMutator::new();
-        splice.mutate(&mut state, &mut input, 0).unwrap();
+        splice.mutate(&mut state, &mut input).unwrap();
 
         log::trace!("{:?}", input.bytes());
 
@@ -584,8 +555,8 @@ mod tests {
 
         let mut equal_in_a_row = 0;
 
-        for i in 0..42 {
-            havoc.mutate(&mut state, &mut input, i).unwrap();
+        for _ in 0..42 {
+            havoc.mutate(&mut state, &mut input).unwrap();
 
             // Make sure we actually mutate something, at least sometimes
             equal_in_a_row = if input == input_prior {
diff --git a/libafl/src/mutators/string.rs b/libafl/src/mutators/string.rs
index ed8cb66097..9217737663 100644
--- a/libafl/src/mutators/string.rs
+++ b/libafl/src/mutators/string.rs
@@ -49,12 +49,7 @@ impl<S> MutatedTransformPost<S> for StringIdentificationMetadata
 where
     S: HasTestcase,
 {
-    fn post_exec(
-        self,
-        state: &mut S,
-        _stage_idx: i32,
-        corpus_idx: Option<CorpusId>,
-    ) -> Result<(), Error> {
+    fn post_exec(self, state: &mut S, corpus_idx: Option<CorpusId>) -> Result<(), Error> {
         if let Some(corpus_idx) = corpus_idx {
             let mut tc = state.testcase_mut(corpus_idx)?;
             tc.add_metadata(self);
@@ -284,12 +279,7 @@ impl<S> Mutator<UnicodeInput, S> for StringCategoryRandMutator
 where
     S: HasRand + HasMaxSize,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut UnicodeInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut UnicodeInput) -> Result<MutationResult, Error> {
         if input.0.bytes().is_empty() {
             return Ok(MutationResult::Skipped);
         }
@@ -347,12 +337,7 @@ impl<S> Mutator<UnicodeInput, S> for StringSubcategoryRandMutator
 where
     S: HasRand + HasMaxSize,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut UnicodeInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut UnicodeInput) -> Result<MutationResult, Error> {
         if input.0.bytes().is_empty() {
             return Ok(MutationResult::Skipped);
         }
@@ -398,12 +383,7 @@ impl<S> Mutator<UnicodeInput, S> for StringCategoryTokenReplaceMutator
 where
     S: HasRand + HasMaxSize + HasMetadata,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut UnicodeInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut UnicodeInput) -> Result<MutationResult, Error> {
         if input.0.bytes().is_empty() {
             return Ok(MutationResult::Skipped);
         }
@@ -462,12 +442,7 @@ impl<S> Mutator<UnicodeInput, S> for StringSubcategoryTokenReplaceMutator
 where
     S: HasRand + HasMaxSize + HasMetadata,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut UnicodeInput,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut UnicodeInput) -> Result<MutationResult, Error> {
         if input.0.bytes().is_empty() {
             return Ok(MutationResult::Skipped);
         }
@@ -544,7 +519,7 @@ mod test {
             for _ in 0..(1 << 12) {
                 let metadata = extract_metadata(bytes.bytes());
                 let mut input = (bytes, metadata);
-                let _ = mutator.mutate(&mut state, &mut input, 0);
+                let _ = mutator.mutate(&mut state, &mut input);
                 println!("{:?}", core::str::from_utf8(input.0.bytes()).unwrap());
                 bytes = input.0;
             }
@@ -576,7 +551,7 @@ mod test {
             for _ in 0..(1 << 12) {
                 let metadata = extract_metadata(bytes.bytes());
                 let mut input = (bytes, metadata);
-                let _ = mutator.mutate(&mut state, &mut input, 0);
+                let _ = mutator.mutate(&mut state, &mut input);
                 println!("{:?}", core::str::from_utf8(input.0.bytes()).unwrap());
                 bytes = input.0;
             }
diff --git a/libafl/src/mutators/token_mutations.rs b/libafl/src/mutators/token_mutations.rs
index d72af63896..270f581ca4 100644
--- a/libafl/src/mutators/token_mutations.rs
+++ b/libafl/src/mutators/token_mutations.rs
@@ -23,6 +23,7 @@ use serde::{Deserialize, Serialize};
 #[cfg(feature = "std")]
 use crate::mutators::str_decode;
 use crate::{
+    corpus::{CorpusId, HasCurrentCorpusIdx},
     inputs::{HasBytesVec, UsesInput},
     mutators::{
         buffer_self_copy, mutations::buffer_copy, MultiMutator, MutationResult, Mutator, Named,
@@ -306,12 +307,7 @@ where
     S: HasMetadata + HasRand + HasMaxSize,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let max_size = state.max_size();
         let tokens_len = {
             let Some(meta) = state.metadata_map().get::<Tokens>() else {
@@ -373,12 +369,7 @@ where
     S: UsesInput + HasMetadata + HasRand + HasMaxSize,
     I: HasBytesVec,
 {
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let size = input.bytes().len();
         if size == 0 {
             return Ok(MutationResult::Skipped);
@@ -437,12 +428,7 @@ where
     I: HasBytesVec,
 {
     #[allow(clippy::too_many_lines)]
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
         let size = input.bytes().len();
         if size == 0 {
             return Ok(MutationResult::Skipped);
@@ -629,6 +615,9 @@ pub struct AFLppRedQueen {
     enable_transform: bool,
     enable_arith: bool,
     text_type: TextType,
+    /// We use this variable to check if we scheduled a new `corpus_idx`
+    /// - and, hence, need to recalculate `text_type`
+    last_corpus_idx: Option<CorpusId>,
 }
 
 impl AFLppRedQueen {
@@ -1095,7 +1084,7 @@ impl AFLppRedQueen {
 
 impl<I, S> MultiMutator<I, S> for AFLppRedQueen
 where
-    S: UsesInput + HasMetadata + HasRand + HasMaxSize + HasCorpus,
+    S: UsesInput + HasMetadata + HasRand + HasMaxSize + HasCorpus + HasCurrentCorpusIdx,
     I: HasBytesVec + From<Vec<u8>>,
 {
     #[allow(clippy::needless_range_loop)]
@@ -1104,7 +1093,6 @@ where
         &mut self,
         state: &mut S,
         input: &I,
-        stage_idx: i32,
         max_count: Option<usize>,
     ) -> Result<Vec<I>, Error> {
         // TODO
@@ -1144,8 +1132,10 @@ where
         // println!("orig: {:#?} new: {:#?}", orig_cmpvals, new_cmpvals);
 
         // Compute when mutating it for the 1st time.
-        if stage_idx == 0 {
+        let current_corpus_idx = state.current_corpus_idx()?.ok_or_else(|| Error::key_not_found("No corpus-idx is currently being fuzzed, but called AFLppRedQueen::multi_mutated()."))?;
+        if self.last_corpus_idx.is_none() || self.last_corpus_idx.unwrap() != current_corpus_idx {
             self.text_type = check_if_text(orig_bytes, orig_bytes.len());
+            self.last_corpus_idx = Some(current_corpus_idx);
         }
         // println!("approximate size: {cmp_len} x {input_len}");
         for cmp_idx in 0..cmp_len {
@@ -1696,6 +1686,7 @@ impl AFLppRedQueen {
             enable_transform: false,
             enable_arith: false,
             text_type: TextType::None,
+            last_corpus_idx: None,
         }
     }
 
@@ -1706,6 +1697,7 @@ impl AFLppRedQueen {
             enable_transform: transform,
             enable_arith: arith,
             text_type: TextType::None,
+            last_corpus_idx: None,
         }
     }
 
diff --git a/libafl/src/mutators/tuneable.rs b/libafl/src/mutators/tuneable.rs
index 1a5b949941..d5c02dc486 100644
--- a/libafl/src/mutators/tuneable.rs
+++ b/libafl/src/mutators/tuneable.rs
@@ -112,13 +112,8 @@ where
     S: HasRand + HasMetadata,
 {
     #[inline]
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut I,
-        stage_id: i32,
-    ) -> Result<MutationResult, Error> {
-        self.scheduled_mutate(state, input, stage_id)
+    fn mutate(&mut self, state: &mut S, input: &mut I) -> Result<MutationResult, Error> {
+        self.scheduled_mutate(state, input)
     }
 }
 
diff --git a/libafl/src/stages/mutational.rs b/libafl/src/stages/mutational.rs
index f22b7ada91..0f6a453e42 100644
--- a/libafl/src/stages/mutational.rs
+++ b/libafl/src/stages/mutational.rs
@@ -29,12 +29,7 @@ use crate::{monitors::PerfFeature, state::HasClientPerfMonitor};
 pub trait MutatedTransformPost<S>: Sized {
     /// Perform any post-execution steps necessary for the transformed input (e.g., updating metadata)
     #[inline]
-    fn post_exec(
-        self,
-        state: &mut S,
-        stage_idx: i32,
-        new_corpus_idx: Option<CorpusId>,
-    ) -> Result<(), Error> {
+    fn post_exec(self, state: &mut S, new_corpus_idx: Option<CorpusId>) -> Result<(), Error> {
         Ok(())
     }
 }
@@ -123,11 +118,11 @@ where
         drop(testcase);
         mark_feature_time!(state, PerfFeature::GetInputFromCorpus);
 
-        for i in 0..num {
+        for _ in 0..num {
             let mut input = input.clone();
 
             start_timer!(state);
-            let mutated = self.mutator_mut().mutate(state, &mut input, i as i32)?;
+            let mutated = self.mutator_mut().mutate(state, &mut input)?;
             mark_feature_time!(state, PerfFeature::Mutate);
 
             if mutated == MutationResult::Skipped {
@@ -139,8 +134,8 @@ where
             let (_, corpus_idx) = fuzzer.evaluate_input(state, executor, manager, untransformed)?;
 
             start_timer!(state);
-            self.mutator_mut().post_exec(state, i as i32, corpus_idx)?;
-            post.post_exec(state, i as i32, corpus_idx)?;
+            self.mutator_mut().post_exec(state, corpus_idx)?;
+            post.post_exec(state, corpus_idx)?;
             mark_feature_time!(state, PerfFeature::MutatePostExec);
         }
 
@@ -354,14 +349,14 @@ where
         };
         drop(testcase);
 
-        let generated = self.mutator.multi_mutate(state, &input, 0, None)?;
+        let generated = self.mutator.multi_mutate(state, &input, None)?;
         // println!("Generated {}", generated.len());
-        for (i, new_input) in generated.into_iter().enumerate() {
+        for new_input in generated {
             // Time is measured directly the `evaluate_input` function
             let (untransformed, post) = new_input.try_transform_into(state)?;
             let (_, corpus_idx) = fuzzer.evaluate_input(state, executor, manager, untransformed)?;
-            self.mutator.multi_post_exec(state, i as i32, corpus_idx)?;
-            post.post_exec(state, i as i32, corpus_idx)?;
+            self.mutator.multi_post_exec(state, corpus_idx)?;
+            post.post_exec(state, corpus_idx)?;
         }
         // println!("Found {}", found);
 
diff --git a/libafl/src/stages/push/mutational.rs b/libafl/src/stages/push/mutational.rs
index f82ff27f9e..47ff29453a 100644
--- a/libafl/src/stages/push/mutational.rs
+++ b/libafl/src/stages/push/mutational.rs
@@ -53,8 +53,6 @@ where
     testcases_to_do: usize,
     testcases_done: usize,
 
-    stage_idx: i32,
-
     mutator: M,
 
     psh: PushStageHelper<CS, EM, OT, Z>,
@@ -150,9 +148,7 @@ where
         mark_feature_time!(state, PerfFeature::GetInputFromCorpus);
 
         start_timer!(state);
-        self.mutator
-            .mutate(state, &mut input, self.stage_idx)
-            .unwrap();
+        self.mutator.mutate(state, &mut input).unwrap();
         mark_feature_time!(state, PerfFeature::Mutate);
 
         self.push_stage_helper_mut()
@@ -176,8 +172,7 @@ where
         fuzzer.process_execution(state, event_mgr, last_input, observers, &exit_kind, true)?;
 
         start_timer!(state);
-        self.mutator
-            .post_exec(state, self.stage_idx, self.current_corpus_idx)?;
+        self.mutator.post_exec(state, self.current_corpus_idx)?;
         mark_feature_time!(state, PerfFeature::MutatePostExec);
         self.testcases_done += 1;
 
@@ -234,7 +229,6 @@ where
         mutator: M,
         shared_state: Rc<RefCell<Option<PushStageSharedState<CS, EM, OT, Z>>>>,
         exit_kind: Rc<Cell<Option<ExitKind>>>,
-        stage_idx: i32,
     ) -> Self {
         Self {
             mutator,
@@ -242,7 +236,6 @@ where
             current_corpus_idx: None, // todo
             testcases_to_do: 0,
             testcases_done: 0,
-            stage_idx,
         }
     }
 }
diff --git a/libafl/src/stages/tmin.rs b/libafl/src/stages/tmin.rs
index 271456e7ed..65594f257d 100644
--- a/libafl/src/stages/tmin.rs
+++ b/libafl/src/stages/tmin.rs
@@ -100,7 +100,7 @@ where
             state.set_max_size(before_len);
 
             start_timer!(state);
-            let mutated = self.mutator_mut().mutate(state, &mut input, i as i32)?;
+            let mutated = self.mutator_mut().mutate(state, &mut input)?;
             mark_feature_time!(state, PerfFeature::Mutate);
 
             if mutated == MutationResult::Skipped {
@@ -148,7 +148,7 @@ where
             };
 
             start_timer!(state);
-            self.mutator_mut().post_exec(state, i as i32, corpus_idx)?;
+            self.mutator_mut().post_exec(state, corpus_idx)?;
             mark_feature_time!(state, PerfFeature::MutatePostExec);
 
             i = next_i;
diff --git a/libafl/src/stages/tuneable.rs b/libafl/src/stages/tuneable.rs
index 496c8016ca..9c386d4aa6 100644
--- a/libafl/src/stages/tuneable.rs
+++ b/libafl/src/stages/tuneable.rs
@@ -195,36 +195,36 @@ where
             (Some(fuzz_time), Some(iters)) => {
                 // perform n iterations or fuzz for provided time, whichever comes first
                 let start_time = current_time();
-                for i in 1..=iters {
+                for _ in 1..=iters {
                     if current_time() - start_time >= fuzz_time {
                         break;
                     }
 
-                    self.perform_mutation(fuzzer, executor, state, manager, &input, i)?;
+                    self.perform_mutation(fuzzer, executor, state, manager, &input)?;
                 }
             }
             (Some(fuzz_time), None) => {
                 // fuzz for provided time
                 let start_time = current_time();
-                for i in 1.. {
+                for _ in 1.. {
                     if current_time() - start_time >= fuzz_time {
                         break;
                     }
 
-                    self.perform_mutation(fuzzer, executor, state, manager, &input, i)?;
+                    self.perform_mutation(fuzzer, executor, state, manager, &input)?;
                 }
             }
             (None, Some(iters)) => {
                 // perform n iterations
-                for i in 1..=iters {
-                    self.perform_mutation(fuzzer, executor, state, manager, &input, i)?;
+                for _ in 1..=iters {
+                    self.perform_mutation(fuzzer, executor, state, manager, &input)?;
                 }
             }
             (None, None) => {
                 // fall back to random
                 let iters = self.iterations(state)? - self.execs_since_progress_start(state)?;
-                for i in 1..=iters {
-                    self.perform_mutation(fuzzer, executor, state, manager, &input, i)?;
+                for _ in 1..=iters {
+                    self.perform_mutation(fuzzer, executor, state, manager, &input)?;
                 }
             }
         }
@@ -444,14 +444,11 @@ where
         state: &mut Z::State,
         manager: &mut EM,
         input: &I,
-        stage_idx: u64,
     ) -> Result<(), Error> {
         let mut input = input.clone();
 
         start_timer!(state);
-        let mutated = self
-            .mutator_mut()
-            .mutate(state, &mut input, stage_idx as i32)?;
+        let mutated = self.mutator_mut().mutate(state, &mut input)?;
         mark_feature_time!(state, PerfFeature::Mutate);
 
         if mutated == MutationResult::Skipped {
@@ -463,9 +460,8 @@ where
         let (_, corpus_idx) = fuzzer.evaluate_input(state, executor, manager, untransformed)?;
 
         start_timer!(state);
-        self.mutator_mut()
-            .post_exec(state, stage_idx as i32, corpus_idx)?;
-        post.post_exec(state, stage_idx as i32, corpus_idx)?;
+        self.mutator_mut().post_exec(state, corpus_idx)?;
+        post.post_exec(state, corpus_idx)?;
         mark_feature_time!(state, PerfFeature::MutatePostExec);
 
         Ok(())
diff --git a/libafl_targets/src/libfuzzer/mutators.rs b/libafl_targets/src/libfuzzer/mutators.rs
index ed2f81d772..d0ebd2b617 100644
--- a/libafl_targets/src/libfuzzer/mutators.rs
+++ b/libafl_targets/src/libfuzzer/mutators.rs
@@ -87,7 +87,6 @@ struct MutatorProxy<'a, M, MT, S> {
     /// The result of mutation, to be propagated to the mutational stage
     result: Rc<RefCell<Result<MutationResult, Error>>>,
     /// Stage index, which is used by libafl mutator implementations
-    stage_idx: i32,
     phantom: PhantomData<(&'a mut (), MT)>,
 }
 
@@ -97,13 +96,11 @@ impl<'a, M, MT, S> MutatorProxy<'a, M, MT, S> {
         state: &'a mut S,
         mutator: &Rc<RefCell<M>>,
         result: &Rc<RefCell<Result<MutationResult, Error>>>,
-        stage_idx: i32,
     ) -> Self {
         Self {
             state: Rc::new(RefCell::new(state)),
             mutator: Rc::downgrade(mutator),
             result: result.clone(),
-            stage_idx,
             phantom: PhantomData,
         }
     }
@@ -126,7 +123,6 @@ impl<'a, M, MT, S> MutatorProxy<'a, M, MT, S> {
                 false
             },
             mutator: self.mutator.clone(),
-            stage_idx: self.stage_idx,
             result: self.result.clone(),
             phantom: PhantomData,
         }
@@ -143,7 +139,7 @@ struct WeakMutatorProxy<F, M, MT, S> {
     /// A weak reference to the mutator
     mutator: Weak<RefCell<M>>,
     /// The stage index to provide to the mutator, when executed.
-    stage_idx: i32,
+
     /// The result of mutation, to be propagated to the mutational stage
     result: Rc<RefCell<Result<MutationResult, Error>>>,
     phantom: PhantomData<(MT, S)>,
@@ -165,7 +161,7 @@ where
                         BytesInput::from(unsafe { core::slice::from_raw_parts(data, size) });
                     let old = state.max_size();
                     state.set_max_size(max_size);
-                    let res = mutator.scheduled_mutate(state, &mut intermediary, self.stage_idx);
+                    let res = mutator.scheduled_mutate(state, &mut intermediary);
                     state.set_max_size(old);
                     let succeeded = res.is_ok();
 
@@ -295,13 +291,8 @@ where
     SM: ScheduledMutator<BytesInput, MT, S> + 'static,
 {
     #[inline]
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut S::Input,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
-        self.scheduled_mutate(state, input, stage_idx)
+    fn mutate(&mut self, state: &mut S, input: &mut S::Input) -> Result<MutationResult, Error> {
+        self.scheduled_mutate(state, input)
     }
 }
 
@@ -325,7 +316,6 @@ where
         &mut self,
         state: &mut S,
         input: &mut S::Input,
-        stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         let seed = state.rand_mut().next();
         let target = input.bytes();
@@ -335,7 +325,7 @@ where
 
         // we assume that the fuzzer did not use this mutator, but instead utilised their own
         let result = Rc::new(RefCell::new(Ok(MutationResult::Mutated)));
-        let proxy = MutatorProxy::new(state, &self.mutator, &result, stage_idx);
+        let proxy = MutatorProxy::new(state, &self.mutator, &result);
         let old = MUTATOR.with(|mutator| {
             let mut mutator = mutator.borrow_mut();
             mutator.replace(Box::new(proxy.weak()))
@@ -375,13 +365,8 @@ where
     SM: ScheduledMutator<BytesInput, MT, S> + 'static,
 {
     #[inline]
-    fn mutate(
-        &mut self,
-        state: &mut S,
-        input: &mut S::Input,
-        stage_idx: i32,
-    ) -> Result<MutationResult, Error> {
-        self.scheduled_mutate(state, input, stage_idx)
+    fn mutate(&mut self, state: &mut S, input: &mut S::Input) -> Result<MutationResult, Error> {
+        self.scheduled_mutate(state, input)
     }
 }
 
@@ -405,7 +390,6 @@ where
         &mut self,
         state: &mut S,
         input: &mut S::Input,
-        stage_idx: i32,
     ) -> Result<MutationResult, Error> {
         // We don't want to use the testcase we're already using for splicing
         let idx = random_corpus_id!(state.corpus(), state.rand_mut());
@@ -426,7 +410,7 @@ where
 
         // we assume that the fuzzer did not use this mutator, but instead utilised their own
         let result = Rc::new(RefCell::new(Ok(MutationResult::Mutated)));
-        let proxy = MutatorProxy::new(state, &self.mutator, &result, stage_idx);
+        let proxy = MutatorProxy::new(state, &self.mutator, &result);
         let old = MUTATOR.with(|mutator| {
             let mut mutator = mutator.borrow_mut();
             mutator.replace(Box::new(proxy.weak()))