Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
Some hostile mobs(zombies, skeletons, creepers.. etc.) are invisible and I cannot attack them with melee weapons. But I can give them a damage with projectiles. I don't know every hostile mobs and friendly mobs are invisible too, but I checked about zombies, skeletons, creepers, and spiders.

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...