Scorpion's Sting

The math is the whole design lever: -3/-3 at instant speed for two mana kills anything with three or fewer toughness, while leaving the option to shrink something bigger out of a blocking or racing math problem. That trade (raw efficiency against a toughness ceiling) is the ancient tension in this style of black removal, going back to the earliest fixed-number debuffs that priced their power in exactly how many toughness points they were allowed to subtract. What distinguishes a modifier like this from hard destruction is not that destruction is worse (it usually is not, outright removal ignores toughness and clears the board of tokens all the same) but that a debuff plays a different game entirely: it can fizzle a combat trick, blank a firebreathing pump, or ambush an unblocked attacker mid-swing, at the cost of whiffing on anything past its size threshold. Three is a deliberate number: enough to answer most of the aggressive early creatures a two-mana instant is meant to trade with, short of the midrange and top-end bodies a color paying more for its removal is supposed to leave standing. The instant timing is what earns the slot over a sorcery-speed equivalent. Holding it open converts a proactive answer into a combat-step response, letting the caster react to attacks, blocks, and pump spells rather than committing the removal on their own turn.