Calamity of the Titans is a rare Sorcery card from Commander Masters (CMM), collector number 745. Current market price: $4.11 (foil $5.43), TCGplayer market prices via Scryfall.
As an additional cost to cast this spell, reveal a colorless creature card from your hand. Exile each creature and planeswalker with mana value less than the revealed card's mana value.