Cottonmouth may refer to: Snakes Agkistrodon piscivorus, a.k.a. the water moccasin, a venomous and semiaquatic pitviper found in the United States. Agkistrodon contortrix mokasen, a.k.a. the northern copperhead, a venomous pitviper found in the United States. Entertainment: O-Ren Ishii, the codename of character in the movie Kill Bill. Cottonmouth, a supervillain in the fictional Marvel Comics universe. A song by the Melvins. A song by Todd Bowie from his Lucky Space People CD (2005). A song by… (More on Cottonmouth)