Volcanic Salvo is a rare Sorcery card from Core Set 2021 Promos (PM21), collector number 172p. Current market price: $0.20 (foil $0.40), 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.