U.S.Agent, John Walker is a uncommon Legendary Creature — Human Soldier Hero card from Marvel Super Heroes (MSH), collector number 236. Current market price: $0.09 (foil $0.27), TCGplayer market prices via Scryfall.
When U.S.Agent enters, create a colorless Equipment artifact token named Sturdy Shield with "Equipped creature gets +1/+2" and equip {2}. Attach it to U.S.Agent.