Magical Mimics are evil shape-shifting creatures, one of the two known breeds of Erbs.
Like their fellow Erbs, the Phanfasms of Mount Phantastico, the Mimics are inherently and irredeemably malevolent beings; they dwell in the hollows of Mount Illuso. The Mimics differ in that they are chronic shape-shifters whose original or true forms (if indeed that have such) are unknown. The Mimics habitually change among repulsive physical shapes — like an ape body with the head of an alligator, or a serpent with black butterfly wings, or a toad with a hyena's head. The Mimics also have one special trick: they can copy the shapes of humans merely by stepping into their shadows.
The Mimics are also comparatively secretive, so that they are less well-known to the outside world. This can render them an even more insidious enemy. (The Magical Mimics in Oz)