As stated in the title, modifying plains biome file can cause world crash. The weird thing in this is that when loading the world for the first time it'll work just fine and there will be no errors in the console output, however when we try to reenter the world, after just a moment, console will be spammed with.

Received invalid biome id: -1

If we're "lucky", the game will crash for itself and the critical error message will be the one seen below

The only thing I've changed are the water and water fog colors. All the different stuff is exactly the same as in worldgen files for 21w14a