When Creepers fall less than 1 block their explotion skin activates.
What I expected to happen was...:
Nothing
What actually happened was...:
Creeper looked like it was exploding but did not.
Steps to Reproduce:
1. make a slime block floor
2. drop a creeper from more than 5 blocks on top of it
3. wait and watch
This issue has been reported already. It has been linked to the original bugreport.
Please search before reporting any bugs, as it's likely that one exists already.