Little is known of Cottonmouth's history before he joined the team of professional criminals known as the Serpent Society, though it is known that he was criminally active in the southern United States. Cottonmouth was one of the charter members of the group, and of the Serpents he played one of the most active parts in the assassination of M.O.D.O.K., using his fangs to bite him.
When the terrorist Viper took control of the Society by force, Cottonmouth at first remained loyal to its leader Sidewinder, but when Viper poisoned him, he submitted to her will, and tried to bite his teammate Diamondback when she tried to rescue him.
Cottonmouth stayed with the Society when its leadership was again taken over, this time by King Cobra, and has remained with them ever since.
Deadpool shot and killed him while Cottonmouth and the Society attacked Marcus Johnson.
In Other Media
Marvel Disk Wars: The Avengers
Cottonmouth is a member of the Serpent Society in the anime series Marvel Disk Wars: The Avengers. He was voiced by Masaya Takatsuka.
Cottonmouth appears as a playable character in Lego Marvel's Avengers.