Throat Slitter is a rare Creature — Rat Ninja card from Secret Lair Drop (SLD), collector number 2356. Current market price: $4.61 (foil $4.15), 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.