So i found out if you Pick up a Necromancer from Iron Spells and Spellbooks in a Mobyoinker and try to release it, to put it into a Containment Jar ( Ars). It will crash the game. It works fine if you lure the necromancer there so im guessing it has something to do with the mob yoinker.

Game version is 0.2.25

All the Mods 9-0.2.28 still crashes