Volcanic Salvo is a rare Sorcery card from Core Set 2021 (M21), collector number 371. Current market price: $0.43 (foil $0.66), TCGplayer market prices via Scryfall.
This spell costs {X} less to cast, where X is the total power of creatures you control. Volcanic Salvo deals 6 damage to each of up to two target creatures and/or planeswalkers.