So I created a server the other day for me and my friend to play on, all was going well until he used an Experience Rod on a Mooshroom and crashed both of our clients, I have no clue what happened, hopefully someone can tell us whats wrong!
again, whats mentioned in the stacktrace is ex nihilo adscension. specifically, the method that gets textures for fluids that are inside the barrels. have you put any mod fluid into a barrel? if yes, what fluid from which mod? remove the mod for testing and see if it works now. if it does, update the mod.