I'm trying to come up with something that isn't overdone...
Paras, Endo/Scythe, Endo is a schoolteacher, an insect that has a strange fungus on his back. It occasionally takes over his body and causes him to do strange things. But no matter, he can always just shake it off. Or can he? (Kind of a Jekyll/Hyde thing going on)
...Which still seems too much like everything else. Ah, well.
It only seems overdone because it's so good. But don't worry I have my own ideas