Soulsworn Spirit is a uncommon Creature — Spirit card from Return to Ravnica (RTR), collector number 51. Current market price: $0.15 (foil $0.23), TCGplayer market prices via Scryfall.
This creature can't be blocked. When this creature enters, detain target creature an opponent controls. (Until your next turn, that creature can't attack or block and its activated abilities can't be activated.)