Monsters which get weaker per respawn in -respawn mode?

I've been wondering for a while now if it's possible to make it so enemies respawn as weaker versions in -repsawn mode, has there ever been any mods which achieve this?

I never thought of that, it would be like the corpse is all shot up to hell and missing tissue and bones so that when it is reanimated, it takes less firepower to bring it down......