Suspended Sentence is a rare Instant card from Duskmourn: House of Horror Commander (DSC), collector number 25. Current market price: $1.09, TCGplayer market prices via Scryfall.
Destroy target creature an opponent controls. That player loses 3 life. Exile Suspended Sentence with three time counters on it. Suspend 3—{1}{B} (Rather than cast this card from your hand, you may pay {1}{B} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)