Forge version: 1.12.2- 14.23.5.2837
Twilight Forest version: 3.10.1013
Link to crash log: mootmmot/Crash-Report@6663f80

Steps to reproduce:

1. Go to Fight Hydra
2. Get within range to fight it
3. game crashes?

What I expected to happen: Epic Boss fight with hydra

What happened instead: Game crashed when I got close, won't let me open the world without crashing.

Sometimes happens with liquids. Try reproducing it again in another world. All I can offer.