Muk is a large, sticky, amorphous Pokémon, made of living purple sludge. It has two small eyes with beady black pupils. It also has an enormous mouth with a grey tongue and strands of ooze connecting its top and bottom jaws. While it has no visible legs, it does have two arms with three fingers on each hand. However, it typically keeps one hand tucked in while it extends the other hand. It is a living biohazard, leaking toxins that instantly kill all plant life it touches. Even it being in close proximity to plants will cause them to wilt and die. It can be found in heavily polluted bodies of water, cities and factories.