S1·E13 Deadly is the Black Widow's Bite!
Aired October 31, 2009
Synopsis
After helping the Super Hero Squad in a battle against Screaming Mimi, Abomination and M.O.D.O.K., Black Widow joins the team. However, unknown to them, she is actually Mystique in disguise sent by Dr. Doom to steal the Infinity Fractals from the Vault.