Bituminous Blast is a uncommon Instant card from Forgotten Realms Commander (AFC), collector number 181. Current market price: $0.22, TCGplayer market prices via Scryfall.
Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.) Bituminous Blast deals 4 damage to target creature.