Viper (Madame Hydra)
Viper, formerly known as Madame Hydra, is a fictional character in the Marvel Comics universe who is a foe of the Avengers and the X-Men. The character was created by Jim Steranko and first appeared in Captain America #110 (February 1969).
Read more about Viper (Madame Hydra): Fictional Character Biography, Powers and Abilities, Madame Hydra VI