Bulk Up is a uncommon Instant card from Secrets of Strixhaven Mystical Archive (SOA), collector number 40. Current market price: $0.35 (foil $0.45), TCGplayer market prices via Scryfall.
Double target creature's power until end of turn. Flashback {4}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)