Throat Slitter is a uncommon Creature — Rat Ninja card from Planechase Anthology (PCA), collector number 37. Current market price: $3.75, TCGplayer market prices via Scryfall.
Ninjutsu {2}{B} ({2}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.) Whenever this creature deals combat damage to a player, destroy target nonblack creature that player controls.