diff --git a/README.md b/README.md
index 5ec9daf..68d0de2 100644
--- a/README.md
+++ b/README.md
@@ -261,12 +261,16 @@ our objects.
 After a [long search][sway] for our memory leak, we have found that
 the fix for this is to remove the reference via
 `body.setUserData(null)` when the body is no longer needed (that is,
-in `killBody()` for the respective object). Please ensure this is done
-for any new body types added to EvolvedTD. See #203 for more
-information.
+in `killBody()` for the respective object). Box2D bodies also have
+fixture lists, which similarly need their user data set to null. If we
+ever add joints, they would need to be taken care of as well. Please
+ensure this is done for any new body types added to EvolvedTD. See
+[#203][] and [#205][] for more information.
 
 [lib]: https://github.com/processing/processing/wiki/How-to-Install-a-Contributed-Library
 [sway]: https://sway.com/3xv6q3uMP1SzS6OW
+[#203]: https://github.com/tsoule88/evolvedTD/pull/203
+[#205]: https://github.com/tsoule88/evolvedTD/pull/205
 
 # Data Collection
 
diff --git a/creature.pde b/creature.pde
index e40a12b..868fbea 100644
--- a/creature.pde
+++ b/creature.pde
@@ -610,6 +610,8 @@ class creature {
 
     // remove reference to creature
     body.setUserData(null);
+    for (Fixture f = body.getFixtureList(); f != null; f = f.getNext())
+      f.setUserData(null);
     // Delete the body
     box2d.destroyBody(body);
   }
diff --git a/food.pde b/food.pde
index d4aebe8..5f97d2a 100644
--- a/food.pde
+++ b/food.pde
@@ -51,6 +51,8 @@ class food {
   // This function removes the particle from the box2d world
   void killBody() {
     the_food.setUserData(null);
+    for (Fixture f = the_food.getFixtureList(); f != null; f = f.getNext())
+      f.setUserData(null);
     box2d.destroyBody(the_food);
   }
   
diff --git a/projectile.pde b/projectile.pde
index 0fbdfcb..b17c477 100644
--- a/projectile.pde
+++ b/projectile.pde
@@ -57,6 +57,8 @@ class projectile {
   void killBody() {
     if (the_projectile != null) {
       the_projectile.setUserData(null);
+      for (Fixture f = the_projectile.getFixtureList(); f != null; f = f.getNext())
+        f.setUserData(null);
       box2d.destroyBody(the_projectile);
     }
   }
diff --git a/rocks.pde b/rocks.pde
index 4228623..e110b0b 100644
--- a/rocks.pde
+++ b/rocks.pde
@@ -36,6 +36,8 @@ class rock {
   // This function removes the particle from the box2d world
   void killBody() {
     the_rock.setUserData(null);
+    for (Fixture f = the_rock.getFixtureList(); f != null; f = f.getNext())
+      f.setUserData(null);
     box2d.destroyBody(the_rock);
   }
   
diff --git a/tower.pde b/tower.pde
index bd5fc97..611f8ef 100644
--- a/tower.pde
+++ b/tower.pde
@@ -170,6 +170,8 @@ class tower {
     if (inTransit) {
       if (!wasInTransit) {
         tower_body.setUserData(null);
+        for (Fixture f = tower_body.getFixtureList(); f != null; f = f.getNext())
+          f.setUserData(null);
         box2d.destroyBody(tower_body);
       }
       wasInTransit = true;