Utterly Mad

When modding, item groups are "added" meaning that you just have to write the item_group and the item you want to spawn and it is compatible with the core and all other mods. With monster_groups however, every mod has to write the whole monster group from scratch to add a single monster. So every mod has its own spawn list that does not include the monsters of other mods. The game loads mods in order that you put them in the mod list so the last mod with a spawn list has that spawn list chosen overriding the spawn list form any other mod and the core game itself. If the monster spawn list were made to work like the item spawn list then all three mods could be loaded and you would have animatronics fighting dino's.