Skinthinner

Morph turned removal into ambush, and this is the clean expression of that idea. Sitting face down as an anonymous 2/2, it threatens nothing but what every face-down creature threatens; the cost to call the bluff is finding out which of your creatures dies. The face-up trigger destroys a target nonblack creature and denies regeneration, and because a morph can be flipped any time its controller has priority, the kill resolves at instant speed. That priority window is what makes the card a trap: an opponent attacks, blocks, or commits a creature to combat, and the morph turns up to eat one of them mid-combat for value the board state never priced in. The nonblack restriction is the leash, standard for black's hard removal in this era, and it keeps the card honest in mirrors where everyone fields the same color. What makes the design sing is the layered cost: cheap to deploy as a body, expensive to unlock as a kill spell, with the bluff living in the gap between those two numbers. It is sorcery-speed assassination wearing an instant-speed disguise, and the disguise is the point. The heavier morph cost is deliberate friction: you pay a premium to keep the kill spell hidden until the moment it lands worst for the opponent, which is exactly when an ambush is supposed to spring.