Rapid Fire is a rare Instant card from Legends (LEG), collector number 32. Current market price: $11.08, TCGplayer market prices via Scryfall.
Cast this spell only before blockers are declared. Target creature gains first strike until end of turn. If it doesn't have rampage, that creature gains rampage 2 until end of turn. (Whenever the creature becomes blocked, it gets +2/+2 until end of turn for each creature blocking it beyond the first.)