Cottonmouth may refer to: Agkistrodon piscivorus, a venomous snake found in the United States. Agkistrodon contortrix mokasen, a.k.a. the northern copperhead; another venomous snake found in the United States. 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 The Melvins. A song by Todd Bowie from his Lucky Space People CD (2005). Xerostomia, dryness of the mouth; a medical condition commonly k… (More on Cottonmouth)