JoJo's Bizarre Adventures proposes a couple of interesting . One villain has a power called "The Lovers" he manifests a tiny ,almost microscopic, insect creature which is physically very very weak (or at least the weakest we have seen at that point), but has the ability of going crazy whenever the stand user feels any kind of pain, so he sends the stand inside an opponents ear to their brain and pain centre – whenever he feels any pain The Lovers inflicts that same pain but much worse on his opponent. It's also heavily implied that any pain caused by The Lovers that is above a certain level would be lethal.
Super weak power that is actually really strong if used intelligently.