Me and Artur kind of broke something. It was not my fault. Artur set me a challenge, I accepted thinking it would be just loads of vanilla mobs but he instead spawned in WIP mobs from twilight forest. Best thing I can think of to solve it is to remove twilight forest and load the world and then add it again. It may cause some problems with items in the world and items with players but it would fix most of the problems.