One who is known to munch on the faces of butts, or an individual so irritating that you're almost positive that they munch on the faces of butts. See also: Ass hat.
A Canadian spider who from time to time will jump off the ground and fly a short distance, landing on someone's face. It will then begin to munch and chew on the unfortunate person's face.
Some cooking show: "The rareCanadian facemuncher can sometimes be found in herbal teas and other such drinks."