Stolen Identity is a rare Sorcery card from Gatecrash (GTC), collector number 53. Current market price: $0.32 (foil $2.28), TCGplayer market prices via Scryfall.
Create a token that's a copy of target artifact or creature. Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)