Grim Reminder is a rare Instant card from Mirrodin (MRD), collector number 66. Current market price: $0.28 (foil $0.68), TCGplayer market prices via Scryfall.
Search your library for a nonland card and reveal it. Each opponent who cast a spell this turn with the same name as that card loses 6 life. Then shuffle. {B}{B}: Return this card from your graveyard to your hand. Activate only during your upkeep.