A recent Mortasheen suggestion was to base something on the fact that the Hero Shrew (Scutisorex somereni) has the strongest skeleton known to man, capable of supporting a grown human standing on its tiny, tiny little back.
So I immediately thought that'd be a tiny shrew-like monster who controls an entire extra, external skeleton like a set of power armor.
Could be either bipedal, or a scorpion-like arrangement growing out of its little spine