This mod randomizes all Mob spawns in the game. This includes modded ones. It works in all dimensions and has a config where you can change the number of mobs per biome, weight, min, and max per group of spawning. This can lead to a chaotic experience or a nice one, depending on the mods you use and your luck.
Plans for the future of the mod
I recommend the mod Random Structure Land for an even crazier experience.
You can download the mod Random Dungeon Spawners for the spawners in the vanilla dungeons to be randomized to any hostile mob
Causes procedurally generated dungeons rembling Doom levels to be placed in worlds
Causes procedurally generated dungeons rembling Doom levels to be placed in worlds
