Undercover Operative is a rare Creature — Shapeshifter Rogue card from Streets of New Capenna (SNC), collector number 414. Current market price: $0.45 (foil $0.55), TCGplayer market prices via Scryfall.
You may have this creature enter as a copy of any creature on the battlefield, except it enters with a shield counter on it if you control that creature. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)