diff --git a/afl/src/corpus/mod.rs b/afl/src/corpus/mod.rs
index b8a33d55c4..ea7467a95c 100644
--- a/afl/src/corpus/mod.rs
+++ b/afl/src/corpus/mod.rs
@@ -2,10 +2,10 @@ pub mod testcase;
 pub use testcase::{Testcase, TestcaseMetadata};
 
 use alloc::borrow::ToOwned;
-use alloc::rc::Rc;
 use alloc::vec::Vec;
-use core::cell::RefCell;
 use core::marker::PhantomData;
+use core::ptr;
+
 #[cfg(feature = "std")]
 use std::path::PathBuf;
 
@@ -18,10 +18,10 @@ where
     I: Input,
 {
     /// Get the entries vector field
-    fn entries(&self) -> &[Rc<RefCell<Testcase<I>>>];
+    fn entries(&self) -> &[Testcase<I>];
 
     /// Get the entries vector field (mutable)
-    fn entries_mut(&mut self) -> &mut Vec<Rc<RefCell<Testcase<I>>>>;
+    fn entries_mut(&mut self) -> &mut Vec<Testcase<I>>;
 }
 
 /// Corpus with all current testcases
@@ -36,57 +36,74 @@ where
     }
 
     /// Add an entry to the corpus
-    fn add(&mut self, testcase: Rc<RefCell<Testcase<I>>>) {
+    fn add(&mut self, testcase: Testcase<I>) {
         self.entries_mut().push(testcase);
     }
 
+    /// Replaces the testcase at the given idx
+    fn replace(&mut self, idx: usize, testcase: Testcase<I>) -> Result<(), AflError> {
+        if self.entries_mut().len() < idx {
+            return Err(AflError::KeyNotFound(format!(
+                "Index {} out of bounds",
+                idx
+            )));
+        }
+        self.entries_mut()[idx] = testcase;
+        Ok(())
+    }
+
+    /// Get by id
+    fn get(&self, idx: usize) -> &Testcase<I> {
+        &self.entries()[idx]
+    }
+
     /// Removes an entry from the corpus, returning it if it was present.
-    fn remove(&mut self, entry: &Testcase<I>) -> Option<Rc<RefCell<Testcase<I>>>> {
-        let mut i: usize = 0;
-        let mut found = false;
-        for x in self.entries() {
-            i = i + 1;
-            if &*x.borrow() as *const _ == entry as *const _ {
-                // TODO check if correct
-                found = true;
-                break;
-            }
+    fn remove(&mut self, entry: &Testcase<I>) -> Option<Testcase<I>> {
+        match self.entries().iter().position(|x| ptr::eq(x, entry)) {
+            Some(i) => Some(self.entries_mut().remove(i)),
+            None => None,
         }
-        if !found {
-            return None;
-        }
-        Some(self.entries_mut().remove(i))
     }
 
     /// Gets a random entry
-    fn random_entry(&self, rand: &mut R) -> Result<(Rc<RefCell<Testcase<I>>>, usize), AflError> {
+    fn random_entry(&self, rand: &mut R) -> Result<(&Testcase<I>, usize), AflError> {
         if self.count() == 0 {
             Err(AflError::Empty("No entries in corpus".to_owned()))
         } else {
             let len = { self.entries().len() };
             let id = rand.below(len as u64) as usize;
-            Ok((self.entries()[id].clone(), id))
+            Ok((self.get(id), id))
         }
     }
 
+    /// Returns the testcase for the given idx, with loaded input
+    fn load_testcase(&mut self, idx: usize) -> Result<(), AflError> {
+        let testcase = self.get(idx);
+        // Ensure testcase is loaded
+        match testcase.input() {
+            None => {
+                let new_testcase = match testcase.filename() {
+                    Some(filename) => Testcase::load_from_disk(filename)?,
+                    None => {
+                        return Err(AflError::IllegalState(
+                            "Neither input, nor filename specified for testcase".into(),
+                        ))
+                    }
+                };
+
+                self.replace(idx, new_testcase)?;
+            }
+            _ => (),
+        }
+        Ok(())
+    }
+
     // TODO: IntoIter
     /// Gets the next entry
-    fn next(&mut self, rand: &mut R) -> Result<(Rc<RefCell<Testcase<I>>>, usize), AflError> {
-        self.random_entry(rand)
-    }
-}
+    fn next(&mut self, rand: &mut R) -> Result<(&Testcase<I>, usize), AflError>;
 
-pub trait HasCorpus<C, I, R>
-where
-    C: Corpus<I, R>,
-    I: Input,
-    R: Rand,
-{
-    /// Get the corpus field
-    fn corpus(&self) -> &C;
-
-    /// Get thecorpus field (mutable)
-    fn corpus_mut(&mut self) -> &mut C;
+    /// Returns the testacase we currently use
+    fn current_testcase(&self) -> (&Testcase<I>, usize);
 }
 
 pub struct InMemoryCorpus<I, R>
@@ -94,7 +111,8 @@ where
     I: Input,
     R: Rand,
 {
-    entries: Vec<Rc<RefCell<Testcase<I>>>>,
+    entries: Vec<Testcase<I>>,
+    pos: usize,
     phantom: PhantomData<R>,
 }
 
@@ -103,10 +121,10 @@ where
     I: Input,
     R: Rand,
 {
-    fn entries(&self) -> &[Rc<RefCell<Testcase<I>>>] {
+    fn entries(&self) -> &[Testcase<I>] {
         &self.entries
     }
-    fn entries_mut(&mut self) -> &mut Vec<Rc<RefCell<Testcase<I>>>> {
+    fn entries_mut(&mut self) -> &mut Vec<Testcase<I>> {
         &mut self.entries
     }
 }
@@ -116,7 +134,22 @@ where
     I: Input,
     R: Rand,
 {
-    // Just use the default implementation
+    /// Gets the next entry
+    fn next(&mut self, rand: &mut R) -> Result<(&Testcase<I>, usize), AflError> {
+        if self.count() == 0 {
+            Err(AflError::Empty("No entries in corpus".to_owned()))
+        } else {
+            let len = { self.entries().len() };
+            let id = rand.below(len as u64) as usize;
+            self.pos = id;
+            Ok((self.get(id), id))
+        }
+    }
+
+    /// Returns the testacase we currently use
+    fn current_testcase(&self) -> (&Testcase<I>, usize) {
+        (self.get(self.pos), self.pos)
+    }
 }
 
 impl<I, R> InMemoryCorpus<I, R>
@@ -127,6 +160,7 @@ where
     pub fn new() -> Self {
         InMemoryCorpus {
             entries: vec![],
+            pos: 0,
             phantom: PhantomData,
         }
     }
@@ -138,8 +172,9 @@ where
     I: Input,
     R: Rand,
 {
-    entries: Vec<Rc<RefCell<Testcase<I>>>>,
+    entries: Vec<Testcase<I>>,
     dir_path: PathBuf,
+    pos: usize,
     phantom: PhantomData<R>,
 }
 
@@ -149,10 +184,10 @@ where
     I: Input,
     R: Rand,
 {
-    fn entries(&self) -> &[Rc<RefCell<Testcase<I>>>] {
+    fn entries(&self) -> &[Testcase<I>] {
         &self.entries
     }
-    fn entries_mut(&mut self) -> &mut Vec<Rc<RefCell<Testcase<I>>>> {
+    fn entries_mut(&mut self) -> &mut Vec<Testcase<I>> {
         &mut self.entries
     }
 }
@@ -164,16 +199,35 @@ where
     R: Rand,
 {
     /// Add an entry and save it to disk
-    fn add(&mut self, entry: Rc<RefCell<Testcase<I>>>) {
-        if *entry.borrow().filename() == None {
-            // TODO walk entry metadatas to ask for pices of filename (e.g. :havoc in AFL)
-            let filename = self.dir_path.join(format!("id_{}", &self.entries.len()));
-            let filename_str = filename.to_str().expect("Invalid Path");
-            *entry.borrow_mut().filename_mut() = Some(filename_str.into());
+    fn add(&mut self, mut entry: Testcase<I>) {
+        match entry.filename() {
+            None => {
+                // TODO walk entry metadatas to ask for pices of filename (e.g. :havoc in AFL)
+                let filename = self.dir_path.join(format!("id_{}", &self.entries.len()));
+                let filename_str = filename.to_str().expect("Invalid Path");
+                entry.set_filename(filename_str.into());
+            }
+            _ => {}
         }
         self.entries.push(entry);
     }
 
+    fn current_testcase(&self) -> (&Testcase<I>, usize) {
+        (self.get(self.pos), self.pos)
+    }
+
+    /// Gets the next entry
+    fn next(&mut self, rand: &mut R) -> Result<(&Testcase<I>, usize), AflError> {
+        if self.count() == 0 {
+            Err(AflError::Empty("No entries in corpus".to_owned()))
+        } else {
+            let len = { self.entries().len() };
+            let id = rand.below(len as u64) as usize;
+            self.pos = id;
+            Ok((self.get(id), id))
+        }
+    }
+
     // TODO save and remove files, cache, etc..., ATM use just InMemoryCorpus
 }
 
@@ -187,6 +241,7 @@ where
         OnDiskCorpus {
             dir_path: dir_path,
             entries: vec![],
+            pos: 0,
             phantom: PhantomData,
         }
     }
@@ -211,10 +266,10 @@ where
     I: Input,
     R: Rand,
 {
-    fn entries(&self) -> &[Rc<RefCell<Testcase<I>>>] {
+    fn entries(&self) -> &[Testcase<I>] {
         self.corpus.entries()
     }
-    fn entries_mut(&mut self) -> &mut Vec<Rc<RefCell<Testcase<I>>>> {
+    fn entries_mut(&mut self) -> &mut Vec<Testcase<I>> {
         self.corpus.entries_mut()
     }
 }
@@ -230,22 +285,27 @@ where
         self.corpus.count()
     }
 
-    fn add(&mut self, entry: Rc<RefCell<Testcase<I>>>) {
+    fn add(&mut self, entry: Testcase<I>) {
         self.corpus.add(entry);
     }
 
     /// Removes an entry from the corpus, returning it if it was present.
-    fn remove(&mut self, entry: &Testcase<I>) -> Option<Rc<RefCell<Testcase<I>>>> {
+    fn remove(&mut self, entry: &Testcase<I>) -> Option<Testcase<I>> {
         self.corpus.remove(entry)
     }
 
     /// Gets a random entry
-    fn random_entry(&self, rand: &mut R) -> Result<(Rc<RefCell<Testcase<I>>>, usize), AflError> {
+    fn random_entry(&self, rand: &mut R) -> Result<(&Testcase<I>, usize), AflError> {
         self.corpus.random_entry(rand)
     }
 
+    /// Returns the testacase we currently use
+    fn current_testcase(&self) -> (&Testcase<I>, usize) {
+        (self.get(self.pos - 1), self.pos - 1)
+    }
+
     /// Gets the next entry
-    fn next(&mut self, _rand: &mut R) -> Result<(Rc<RefCell<Testcase<I>>>, usize), AflError> {
+    fn next(&mut self, _rand: &mut R) -> Result<(&Testcase<I>, usize), AflError> {
         self.pos += 1;
         if self.corpus.count() == 0 {
             return Err(AflError::Empty("Corpus".to_owned()));
@@ -255,7 +315,7 @@ where
             self.pos = 1;
             self.cycles += 1;
         }
-        Ok((self.corpus.entries()[self.pos - 1].clone(), self.pos - 1))
+        Ok((&self.corpus.entries()[self.pos - 1], self.pos - 1))
     }
 }
 
@@ -341,7 +401,6 @@ mod tests {
     use crate::inputs::bytes::BytesInput;
     use crate::utils::StdRand;
 
-    use alloc::rc::Rc;
     use std::path::PathBuf;
 
     #[test]
@@ -350,14 +409,12 @@ mod tests {
         let mut q = QueueCorpus::new(OnDiskCorpus::<BytesInput, StdRand>::new(PathBuf::from(
             "fancy/path",
         )));
-        let t: Rc<_> =
-            Testcase::with_filename(BytesInput::new(vec![0 as u8; 4]), "fancyfile".into()).into();
+        let t = Testcase::with_filename(BytesInput::new(vec![0 as u8; 4]), "fancyfile".into());
         q.add(t);
         let filename = q
             .next(&mut rand)
             .unwrap()
             .0
-            .borrow()
             .filename()
             .as_ref()
             .unwrap()
@@ -367,7 +424,6 @@ mod tests {
             q.next(&mut rand)
                 .unwrap()
                 .0
-                .borrow()
                 .filename()
                 .as_ref()
                 .unwrap()
diff --git a/afl/src/corpus/testcase.rs b/afl/src/corpus/testcase.rs
index b2e518d7d8..b4c6d6b696 100644
--- a/afl/src/corpus/testcase.rs
+++ b/afl/src/corpus/testcase.rs
@@ -51,17 +51,10 @@ impl<I> Testcase<I>
 where
     I: Input,
 {
-    /// Make sure to return a valid input instance loading it from disk if not in memory
-    pub fn load_input(&mut self) -> Result<&I, AflError> {
-        if self.input.is_none() {
-            let input = I::from_file(
-                self.filename
-                    .as_ref()
-                    .ok_or(AflError::EmptyOptional("filename not specified".into()))?,
-            )?;
-            self.input = Some(input);
-        }
-        Ok(self.input.as_ref().unwrap())
+    /// Returns this testcase with a loaded input
+    pub fn load_from_disk(filename: &str) -> Result<Self, AflError> {
+        let input = I::from_file(filename)?;
+        Ok(Testcase::new(input))
     }
 
     /// Get the input, if any
diff --git a/afl/src/engines/mod.rs b/afl/src/engines/mod.rs
index d8fec2ed31..cb90ac6793 100644
--- a/afl/src/engines/mod.rs
+++ b/afl/src/engines/mod.rs
@@ -8,7 +8,7 @@ use core::fmt::Debug;
 use core::marker::PhantomData;
 use hashbrown::HashMap;
 
-use crate::corpus::{Corpus, HasCorpus, Testcase};
+use crate::corpus::{Corpus, Testcase};
 use crate::events::{EventManager, LoadInitialEvent, UpdateStatsEvent};
 use crate::executors::Executor;
 use crate::feedbacks::Feedback;
@@ -26,7 +26,7 @@ pub trait StateMetadata: Debug {
     fn name(&self) -> &'static str;
 }
 
-pub trait State<C, E, I, R>: HasCorpus<C, I, R>
+pub trait State<C, E, I, R>
 where
     C: Corpus<I, R>,
     E: Executor<I>,
@@ -111,10 +111,7 @@ where
     fn executor_mut(&mut self) -> &mut E;
 
     /// Runs the input and triggers observers and feedback
-    fn evaluate_input(
-        &mut self,
-        input: I,
-    ) -> Result<(bool, Option<Rc<RefCell<Testcase<I>>>>), AflError> {
+    fn evaluate_input(&mut self, input: &I) -> Result<u32, AflError> {
         self.reset_observers()?;
         self.executor_mut().run_target(&input)?;
         self.set_executions(self.executions() + 1);
@@ -124,29 +121,37 @@ where
         for feedback in self.feedbacks_mut() {
             fitness += feedback.is_interesting(&input)?;
         }
-
-        if fitness > 0 {
-            let testcase: Rc<RefCell<_>> = Testcase::new(input).into();
-            for feedback in self.feedbacks_mut() {
-                feedback.append_metadata(testcase.clone())?;
-            }
-            testcase.borrow_mut().set_fitness(fitness);
-            self.corpus_mut().add(testcase.clone());
-            Ok((true, Some(testcase)))
-        } else {
-            for feedback in self.feedbacks_mut() {
-                feedback.discard_metadata()?;
-            }
-            Ok((false, None))
-        }
+        Ok(fitness)
     }
 
-    fn load_initial_input(&mut self, input: I) -> Result<(), AflError> {
-        // Inefficent clone, but who cares this is done once at init
-        let (_, testcase) = self.evaluate_input(input.clone())?;
-        if testcase.is_none() {
-            let testcase = Testcase::new(input).into();
-            self.corpus_mut().add(testcase);
+    /// Resets all current feedbacks
+    fn discard_input(&mut self, input: &I) -> Result<(), AflError> {
+        // TODO: This could probably be automatic in the feedback somehow?
+        for feedback in self.feedbacks_mut() {
+            feedback.discard_metadata(input)?;
+        }
+        Ok(())
+    }
+
+    /// Creates a new testcase, appending the metadata from each feedback
+    fn input_to_testcase(&mut self, input: I, fitness: u32) -> Result<Testcase<I>, AflError> {
+        let mut testcase = Testcase::new(input);
+        testcase.set_fitness(fitness);
+        for feedback in self.feedbacks_mut() {
+            feedback.append_metadata(&mut testcase)?;
+        }
+
+        Ok(testcase)
+    }
+
+    /// Adds this input to the corpus, if it's intersting
+    fn add_input(&mut self, corpus: &mut C, input: I) -> Result<(), AflError> {
+        let fitness = self.evaluate_input(&input)?;
+        if fitness > 0 {
+            let testcase = self.input_to_testcase(input, fitness)?;
+            corpus.add(testcase);
+        } else {
+            self.discard_input(&input)?;
         }
         Ok(())
     }
@@ -155,6 +160,7 @@ where
 pub fn generate_initial_inputs<S, G, C, E, I, R, EM>(
     rand: &mut R,
     state: &mut S,
+    corpus: &mut C,
     generator: &mut G,
     events: &mut EM,
     num: usize,
@@ -170,7 +176,7 @@ where
 {
     for _ in 0..num {
         let input = generator.generate(rand)?;
-        state.load_initial_input(input)?;
+        state.add_input(corpus, input)?;
         fire_event!(events, LoadInitialEvent)?;
     }
     events.process(state)?;
@@ -190,26 +196,8 @@ where
     // additional_corpuses: HashMap<&'static str, Box<dyn Corpus>>,
     observers: Vec<Rc<RefCell<dyn Observer>>>,
     feedbacks: Vec<Box<dyn Feedback<I>>>,
-    corpus: C,
     executor: E,
-    phantom: PhantomData<R>,
-}
-
-impl<C, E, I, R> HasCorpus<C, I, R> for StdState<C, E, I, R>
-where
-    C: Corpus<I, R>,
-    E: Executor<I>,
-    I: Input,
-    R: Rand,
-{
-    fn corpus(&self) -> &C {
-        &self.corpus
-    }
-
-    /// Get thecorpus field (mutable)
-    fn corpus_mut(&mut self) -> &mut C {
-        &mut self.corpus
-    }
+    phantom: PhantomData<(C, R)>,
 }
 
 impl<C, E, I, R> State<C, E, I, R> for StdState<C, E, I, R>
@@ -274,14 +262,13 @@ where
     I: Input,
     R: Rand,
 {
-    pub fn new(corpus: C, executor: E) -> Self {
+    pub fn new(executor: E) -> Self {
         StdState {
             executions: 0,
             start_time: current_milliseconds(),
             metadatas: HashMap::default(),
             observers: vec![],
             feedbacks: vec![],
-            corpus: corpus,
             executor: executor,
             phantom: PhantomData,
         }
@@ -309,20 +296,38 @@ where
         &mut self,
         rand: &mut R,
         state: &mut S,
+        corpus: &mut C,
         events: &mut EM,
     ) -> Result<usize, AflError> {
-        let (testcase, idx) = state.corpus_mut().next(rand)?;
+        let (testcase, idx) = corpus.next(rand)?;
+        match testcase.input() {
+            None => {
+                // Load from disk.
+                corpus.load_testcase(idx)?;
+            }
+            _ => (),
+        };
+
+        let input = corpus.get(idx).input().as_ref().unwrap();
+
         for stage in self.stages_mut() {
-            stage.perform(rand, state, events, testcase.clone())?;
+            stage.perform(rand, state, corpus, events, &input)?;
         }
+
         events.process(state)?;
         Ok(idx)
     }
 
-    fn fuzz_loop(&mut self, rand: &mut R, state: &mut S, events: &mut EM) -> Result<(), AflError> {
+    fn fuzz_loop(
+        &mut self,
+        rand: &mut R,
+        state: &mut S,
+        corpus: &mut C,
+        events: &mut EM,
+    ) -> Result<(), AflError> {
         let mut last = current_milliseconds();
         loop {
-            self.fuzz_one(rand, state, events)?;
+            self.fuzz_one(rand, state, corpus, events)?;
             let cur = current_milliseconds();
             if cur - last > 60 * 100 {
                 last = cur;
@@ -414,7 +419,7 @@ mod tests {
         corpus.add(testcase);
 
         let executor = InMemoryExecutor::<BytesInput>::new(harness);
-        let mut state = StdState::new(corpus, executor);
+        let mut state = StdState::new(executor);
 
         let mut events_manager = LoggerEventManager::new(stderr());
 
@@ -428,7 +433,7 @@ mod tests {
 
         for i in 0..1000 {
             engine
-                .fuzz_one(&mut rand, &mut state, &mut events_manager)
+                .fuzz_one(&mut rand, &mut state, &mut corpus, &mut events_manager)
                 .expect(&format!("Error in iter {}", i));
         }
     }
diff --git a/afl/src/events/mod.rs b/afl/src/events/mod.rs
index 0faec55cf0..8df9f0a849 100644
--- a/afl/src/events/mod.rs
+++ b/afl/src/events/mod.rs
@@ -8,8 +8,6 @@ pub mod shmem_translated;
 #[cfg(feature = "std")]
 pub use crate::events::llmp::LLMP;
 
-use alloc::rc::Rc;
-use core::cell::RefCell;
 //use core::any::TypeId;
 #[cfg(feature = "std")]
 use std::io::Write;
@@ -87,7 +85,7 @@ pub struct NewTestcaseEvent<I>
 where
     I: Input,
 {
-    testcase: Rc<RefCell<Testcase<I>>>,
+    testcase: Testcase<I>,
 }
 
 impl<I> Event for NewTestcaseEvent<I>
@@ -103,11 +101,11 @@ impl<I> NewTestcaseEvent<I>
 where
     I: Input,
 {
-    pub fn new(testcase: Rc<RefCell<Testcase<I>>>) -> Self {
+    pub fn new(testcase: Testcase<I>) -> Self {
         NewTestcaseEvent { testcase: testcase }
     }
 
-    pub fn testcase(&self) -> &Rc<RefCell<Testcase<I>>> {
+    pub fn testcase(&self) -> &Testcase<I> {
         &self.testcase
     }
 }
@@ -170,10 +168,10 @@ where
         for event in &self.events {
             writeln!(
                 &mut self.writer,
-                "#{}\t[{}] corp: {} exec/s: {}",
+                "#{}\t[{}] exec/s: {}",
                 state.executions(),
                 event,
-                state.corpus().entries().len(),
+                //TODO: Count corpus.entries().len(),
                 state.executions_over_seconds()
             )?;
         }
diff --git a/afl/src/feedbacks/mod.rs b/afl/src/feedbacks/mod.rs
index 2f11da8508..f77f3debe3 100644
--- a/afl/src/feedbacks/mod.rs
+++ b/afl/src/feedbacks/mod.rs
@@ -18,12 +18,12 @@ where
     fn is_interesting(&mut self, input: &I) -> Result<u32, AflError>;
 
     /// Append to the testcase the generated metadata in case of a new corpus item
-    fn append_metadata(&mut self, _testcase: Rc<RefCell<Testcase<I>>>) -> Result<(), AflError> {
+    fn append_metadata(&mut self, _testcase: &mut Testcase<I>) -> Result<(), AflError> {
         Ok(())
     }
 
     /// Discard the stored metadata in case that the testcase is not added to the corpus
-    fn discard_metadata(&mut self) -> Result<(), AflError> {
+    fn discard_metadata(&mut self, _input: &I) -> Result<(), AflError> {
         Ok(())
     }
 }
@@ -230,16 +230,16 @@ where
         Ok(interesting)
     }
 
-    fn append_metadata(&mut self, testcase: Rc<RefCell<Testcase<I>>>) -> Result<(), AflError> {
+    fn append_metadata(&mut self, testcase: &mut Testcase<I>) -> Result<(), AflError> {
         let meta = Box::new(MapNoveltiesMetadata::new(core::mem::take(
             &mut self.novelties,
         )));
-        testcase.borrow_mut().add_metadata(meta);
+        testcase.add_metadata(meta);
         Ok(())
     }
 
     /// Discard the stored metadata in case that the testcase is not added to the corpus
-    fn discard_metadata(&mut self) -> Result<(), AflError> {
+    fn discard_metadata(&mut self, _input: &I) -> Result<(), AflError> {
         self.novelties.clear();
         Ok(())
     }
diff --git a/afl/src/mutators/mod.rs b/afl/src/mutators/mod.rs
index 40dc42d6b5..9067e7f8b0 100644
--- a/afl/src/mutators/mod.rs
+++ b/afl/src/mutators/mod.rs
@@ -4,11 +4,7 @@ pub use scheduled::HavocBytesMutator;
 pub use scheduled::ScheduledMutator;
 pub use scheduled::StdScheduledMutator;
 
-use alloc::rc::Rc;
-use core::cell::RefCell;
-
 use crate::corpus::Corpus;
-use crate::corpus::Testcase;
 use crate::inputs::Input;
 use crate::utils::Rand;
 use crate::AflError;
@@ -23,7 +19,7 @@ where
     fn mutate(
         &mut self,
         rand: &mut R,
-        corpus: &mut C,
+        corpus: &C,
         input: &mut I,
         stage_idx: i32,
     ) -> Result<(), AflError>;
@@ -31,8 +27,8 @@ where
     /// Post-process given the outcome of the execution
     fn post_exec(
         &mut self,
-        _is_interesting: bool,
-        _new_testcase: Option<Rc<RefCell<Testcase<I>>>>,
+        _is_interesting: u32,
+        _input: &I,
         _stage_idx: i32,
     ) -> Result<(), AflError> {
         Ok(())
diff --git a/afl/src/mutators/scheduled.rs b/afl/src/mutators/scheduled.rs
index 84c91c6279..45a85f12d2 100644
--- a/afl/src/mutators/scheduled.rs
+++ b/afl/src/mutators/scheduled.rs
@@ -15,7 +15,7 @@ pub enum MutationResult {
 // TODO maybe the mutator arg is not needed
 /// The generic function type that identifies mutations
 type MutationFunction<M, C, I, R> =
-    fn(&mut M, &mut R, &mut C, &mut I) -> Result<MutationResult, AflError>;
+    fn(&mut M, &mut R, &C, &mut I) -> Result<MutationResult, AflError>;
 
 pub trait ComposedByMutations<C, I, R>
 where
@@ -66,7 +66,7 @@ where
     fn scheduled_mutate(
         &mut self,
         rand: &mut R,
-        corpus: &mut C,
+        corpus: &C,
         input: &mut I,
         _stage_idx: i32,
     ) -> Result<(), AflError> {
@@ -96,7 +96,7 @@ where
     fn mutate(
         &mut self,
         rand: &mut R,
-        corpus: &mut C,
+        corpus: &C,
         input: &mut I,
         _stage_idx: i32,
     ) -> Result<(), AflError> {
@@ -155,7 +155,7 @@ where
 pub fn mutation_bitflip<M, C, I, R>(
     _mutator: &mut M,
     rand: &mut R,
-    _corpus: &mut C,
+    _corpus: &C,
     input: &mut I,
 ) -> Result<MutationResult, AflError>
 where
@@ -179,7 +179,7 @@ where
 pub fn mutation_byteflip<M, C, I, R>(
     _mutator: &mut M,
     rand: &mut R,
-    _corpus: &mut C,
+    _corpus: &C,
     input: &mut I,
 ) -> Result<MutationResult, AflError>
 where
@@ -203,7 +203,7 @@ where
 pub fn mutation_byteinc<M, C, I, R>(
     _mutator: &mut M,
     rand: &mut R,
-    _corpus: &mut C,
+    _corpus: &C,
     input: &mut I,
 ) -> Result<MutationResult, AflError>
 where
@@ -227,7 +227,7 @@ where
 pub fn mutation_bytedec<M, C, I, R>(
     _mutator: &mut M,
     rand: &mut R,
-    _corpus: &mut C,
+    _corpus: &C,
     input: &mut I,
 ) -> Result<MutationResult, AflError>
 where
@@ -251,7 +251,7 @@ where
 pub fn mutation_byteneg<M, C, I, R>(
     _mutator: &mut M,
     rand: &mut R,
-    _corpus: &mut C,
+    _corpus: &C,
     input: &mut I,
 ) -> Result<MutationResult, AflError>
 where
@@ -292,7 +292,7 @@ fn locate_diffs(this: &[u8], other: &[u8]) -> (i64, i64) {
 pub fn mutation_splice<M, C, I, R>(
     _mutator: &mut M,
     rand: &mut R,
-    corpus: &mut C,
+    corpus: &C,
     input: &mut I,
 ) -> Result<MutationResult, AflError>
 where
@@ -301,17 +301,15 @@ where
     I: Input + HasBytesVec,
     R: Rand,
 {
-    // We don't want to use the testcase we're already using for splicing
-    let (other_rr, _) = corpus.random_entry(rand)?.clone();
-    let mut other_testcase = match other_rr.try_borrow_mut() {
-        Ok(x) => x,
-        Err(_) => {
-            return Ok(MutationResult::Skipped);
-        }
-    };
-
-    let other = other_testcase.load_input()?;
+    // TODO: Don't reuse the current testcase!
+    // (We don't want to use the testcase we're already using for splicing)
+    let (other_testcase, _) = corpus.random_entry(rand)?;
+    // TODO: let other = other_testcase.load_input()?;
     // println!("Input: {:?}, other input: {:?}", input.bytes(), other.bytes());
+    let other = match other_testcase.input() {
+        Some(i) => i,
+        None => return Ok(MutationResult::Skipped), // TODO!!
+    };
 
     let mut counter = 0;
     let (first_diff, last_diff) = loop {
@@ -362,7 +360,7 @@ where
     fn mutate(
         &mut self,
         rand: &mut R,
-        corpus: &mut C,
+        corpus: &C,
         input: &mut I,
         stage_idx: i32,
     ) -> Result<(), AflError> {
@@ -380,7 +378,7 @@ where
     /// Create a new HavocBytesMutator instance given a ScheduledMutator to wrap
     pub fn new(mut scheduled: SM) -> Self {
         scheduled.add_mutation(mutation_bitflip);
-        //scheduled.add_mutation(mutation_splice);
+        scheduled.add_mutation(mutation_splice);
         HavocBytesMutator {
             scheduled: scheduled,
             phantom: PhantomData,
@@ -432,13 +430,15 @@ where
 #[cfg(test)]
 mod tests {
     use crate::inputs::BytesInput;
-    use crate::mutators::scheduled::{mutation_splice, StdScheduledMutator};
+    use crate::mutators::scheduled::StdScheduledMutator;
     use crate::utils::{Rand, XKCDRand};
     use crate::{
         corpus::{Corpus, InMemoryCorpus, Testcase},
         inputs::HasBytesVec,
     };
 
+    use super::mutation_splice;
+
     #[test]
     fn test_mut_splice() {
         // With the current impl, seed of 1 will result in a split at pos 2.
@@ -447,11 +447,10 @@ mod tests {
         corpus.add(Testcase::new(vec!['a' as u8, 'b' as u8, 'c' as u8]).into());
         corpus.add(Testcase::new(vec!['d' as u8, 'e' as u8, 'f' as u8]).into());
 
-        let (testcase_rr, _) = corpus
+        let (testcase, _) = corpus
             .next(&mut rand)
             .expect("Corpus did not contain entries");
-        let mut testcase = testcase_rr.borrow_mut();
-        let mut input = testcase.load_input().expect("No input in testcase").clone();
+        let mut input = testcase.input().as_ref().unwrap().clone();
 
         rand.set_seed(5);
         let mut mutator = StdScheduledMutator::new();
diff --git a/afl/src/stages/mod.rs b/afl/src/stages/mod.rs
index 17c8110a78..fe16267980 100644
--- a/afl/src/stages/mod.rs
+++ b/afl/src/stages/mod.rs
@@ -1,10 +1,6 @@
 pub mod mutational;
 pub use mutational::StdMutationalStage;
 
-use alloc::rc::Rc;
-use core::cell::RefCell;
-
-use crate::corpus::testcase::Testcase;
 use crate::corpus::Corpus;
 use crate::engines::State;
 use crate::events::EventManager;
@@ -27,7 +23,8 @@ where
         &mut self,
         rand: &mut R,
         state: &mut S,
+        corpus: &C,
         events: &mut EM,
-        testcase: Rc<RefCell<Testcase<I>>>,
+        input: &I,
     ) -> Result<(), AflError>;
 }
diff --git a/afl/src/stages/mutational.rs b/afl/src/stages/mutational.rs
index 154d3beeda..49433ce4cb 100644
--- a/afl/src/stages/mutational.rs
+++ b/afl/src/stages/mutational.rs
@@ -1,17 +1,15 @@
-use alloc::rc::Rc;
-use core::cell::RefCell;
 use core::marker::PhantomData;
 
-use crate::corpus::testcase::Testcase;
 use crate::engines::State;
-use crate::events::{EventManager, NewTestcaseEvent};
+use crate::events::EventManager;
 use crate::executors::Executor;
 use crate::inputs::Input;
 use crate::mutators::Mutator;
 use crate::stages::Corpus;
 use crate::stages::Stage;
 use crate::utils::Rand;
-use crate::{fire_event, AflError};
+use crate::AflError;
+use crate::{events::NewTestcaseEvent, fire_event};
 
 // TODO multi mutators stage
 
@@ -42,22 +40,27 @@ where
         &mut self,
         rand: &mut R,
         state: &mut S,
+        corpus: &C,
         events: &mut EM,
-        testcase: Rc<RefCell<Testcase<I>>>,
+        input: &I,
     ) -> Result<(), AflError> {
         let num = self.iterations(rand);
         for i in 0..num {
-            let mut input = testcase.borrow_mut().load_input()?.clone();
+            let mut input_mut = input.clone();
             self.mutator_mut()
-                .mutate(rand, state.corpus_mut(), &mut input, i as i32)?;
+                .mutate(rand, corpus, &mut input_mut, i as i32)?;
 
-            let (interesting, new_testcase) = state.evaluate_input(input)?;
+            let interesting = state.evaluate_input(&input_mut)?;
 
             self.mutator_mut()
-                .post_exec(interesting, new_testcase.clone(), i as i32)?;
+                .post_exec(interesting, &input_mut, i as i32)?;
 
-            if !new_testcase.is_none() {
-                fire_event!(events, NewTestcaseEvent<I>, new_testcase.unwrap())?;
+            if interesting > 0 {
+                let new_testcase = state.input_to_testcase(input_mut, interesting)?;
+                fire_event!(events, NewTestcaseEvent<I>, new_testcase)?;
+            //state.corpus_mut().add(new_testcase); // TODO: Probably no longer needed, once events work
+            } else {
+                state.discard_input(&input_mut)?;
             }
         }
         Ok(())
@@ -115,10 +118,11 @@ where
         &mut self,
         rand: &mut R,
         state: &mut S,
+        corpus: &C,
         events: &mut EM,
-        testcase: Rc<RefCell<Testcase<I>>>,
+        input: &I,
     ) -> Result<(), AflError> {
-        self.perform_mutational(rand, state, events, testcase)
+        self.perform_mutational(rand, state, corpus, events, input)
     }
 }