Undercover Operative is a rare Creature — Shapeshifter Rogue card from Streets of New Capenna Promos (PSNC), collector number 63s. Current market price: — (foil $0.80), 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.)