Agent 13, Sharon Carter is a uncommon Legendary Creature — Human Spy Hero card from Marvel Super Heroes (MSH), collector number 1. Current market price: $0.12 (foil $0.25), TCGplayer market prices via Scryfall.
Whenever a creature you control attacks alone, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")