Thanks, well that explains why it’s locking. Maybe there is some other way to accomplish what I want. I am trying to make a mod that makes it so farm animals (cows, sheep, pigs, and chickens) will only spawn near villages. I was worried that if there are other animal mods installed, if I just denied those spawns in the village radius farm animals would be extremely rare, so I was trying to replace any non farm animal spawn near villages with farm animals, even at world creation when larger numbers of passive spawns are created. The reason for the get in radius was so I could detect animal groups and replace them all with one type of animal. Is there possibly a way to detect when a spawn is part of a group of mobs? Or is there some other way to accomplish the spirit of what I’m trying to do, so that farm animals spawn in a good number near villages?