Titanic Brawl is a common Instant card from Ravnica Allegiance (RNA), collector number 146. Current market price: $0.16 (foil $0.46), TCGplayer market prices via Scryfall.
This spell costs {1} less to cast if it targets a creature you control with a +1/+1 counter on it. Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)