The Demiguise is a primate-like creature that resembles a silver-haired orangutan with large, doleful black eyes.
It has the remarkable ability to become invisible at will, and has precognitive sight, so the only way to catch it is to do something completely unpredictable.
The Demiguise is fundamentally a peaceful beast, but it will give a rather nasty nip when provoked or feels threatened.
Unfortunately for the Demiguise, its long, silky, silvery hair can be spun into Invisibility Cloaks, making its pelt highly valuable.
Fantastic Beasts and where to find them