Trial of Agony is a uncommon Sorcery card from Duskmourn: House of Horror (DSK), collector number 159. Current market price: $0.21 (foil $0.30), TCGplayer market prices via Scryfall.
Choose two target creatures controlled by the same opponent. That player chooses one of those creatures. Trial of Agony deals 5 damage to that creature, and the other can't block this turn.