Scarlet Witch, Chaotic Avenger is a rare Legendary Creature — Mutant Warlock Hero card from Marvel Super Heroes Commander (MSC), collector number 414. Current market price: $7.94, TCGplayer market prices via Scryfall.
Flying Whenever Scarlet Witch deals combat damage to a player, look at the top two cards of your library, then exile them face down. Then you may cast a Hero or noncreature spell from among cards exiled with Scarlet Witch without paying its mana cost.