Parasites?

[DMH]

Parasites do not kill their host. They are symbiotes that live on or in their host and feed off of it. Other than the FF, Silverthorne's Template Troves III is the only source I can think of.

What you are looking for are parasitoids and the MM V critter mentioned above fits the bill as does spider eater, vinespawn (MM V), meanlocks (MM II), yellow musk creeper (FF) and the mindshredders (MM III) among others.

 

[talien]

Meenlocks definitely fit the bill, but I wouldn't count undead. Or green slime, since it doesn't create a creature (but maybe olive slime does, can't recall).

It seems like MMV included quite a few parasites. I'm going to have to pick it up now for sure.