"From Muk's body seeps a foul fluid that gives off a nose-bendingly horrible stench. Just one drop of this Pokémon's body fluid can turn a pool stagnant and rancid."
Muk is easily one of the grossest Pokemon ever. In fact, it took until Generation V to get two Pokemon that literally out-rank Muk. Muk is literally a body of slime so foul, that its stench can seep through the Pokeball. Don't believe me? Look up Professor Oak receiving Muk from Ash and see his reaction.
Its Basic Attacks are Lick, Poison Jab. While its Special Attacks are Dark Pulse, Gunk Shot, and Sludge Bomb.