Wisecrack

Red rarely gets to kill creatures by name; it deals damage, and toughness is the wall it keeps running into. This one sidesteps the wall by turning a creature's own power against it, which means the bigger the attacker's swing, the surer the kill. A 6/6 obliterates itself; a wide-bodied wall with low power and high toughness (a 1/4, say) shrugs off the single point it deals and lives. That inversion is the whole design axis: you are not paying for a fixed damage number, you are paying for whatever the opponent has invested in offense, so the card scales with the threat instead of against it. The attacking-creature clause sharpens the pitch into a defensive tool with teeth, taxing the controller for two when you snipe an aggressor mid-swing, so the card punishes commitment to the red zone rather than sitting on a stalled board. The catch is symmetric to the payoff: a zero-power creature cannot be scratched at all, and a token swarm eats the spell one member at a time while the rest keep coming. It reads as a combat trick played from the defender's chair, best held for the turn an opponent overextends into an attack, when it removes a threat and clips a little life off the top for the road.