Describe the crash
Was climbing a mountain when a zombie fell on my head and hit me, causing my game to crash. Letting the zombie hit me again after loading back in did not cause another crash.

To Reproduce
Steps to reproduce the behavior:
Not sure. Maybe get hit by a falling zombie?

Crash Log
https://pastebin.com/CTRn8KqC

Info (please complete the following information):

• Modpack Version: 2.77.5
• Server or Singleplayer: Singleplayer
• Version the world was created on: 2.77.5

Additional context
The culprit:

Duplicate of #296