Put the summary of the bug you're having here

What I expected to happen was...:
I expected to see a silverfish that I could kill.

What actually happened was...:
The silverfish and spider were invisiable. I think they were in the ground attacking me. They weren't using a potion because they were not there, there was no wavyness they were completely missing.

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...I happens at random the best shot is to go were there are a lot of silverfish(end portal in stronghold).
3. ...