heh, thats like something that happened to me on a singleplayer superflat on hard whislt on a computer that could not run minecraft, i ran out of ram and there was mobs everywhere, all facing the same direction
For some reason modded mobs spawn more of themselves if you unload them and go back into the chunk.similar thing happened with grasshoppers in the Erebus today. Forgot to take a screenshot tho.
There is a mod called zombie awareness? Or mob awareness? I can't remember what the mod is called exactly. Zombies attract other zombies