Prizefight is a common Instant card from Streets of New Capenna (SNC), collector number 154. Current market price: $0.34 (foil $0.41), TCGplayer market prices via Scryfall.
Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.) Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")