Throttle

Black's -X/-X removal template exists to solve problems that destruction cannot: it kills indestructible creatures, shrinks the survivors of a toughness-pumped board rather than leaving them whole, and can be pointed at a blocker mid-combat to break the damage math open. Throttle offers a wide, clean version of that effect, four flat points of toughness reduction at instant speed with no conditions clipped onto it: no restriction on the creature's color, no life payment, no death trigger to enable. The catch is the price. Its cheaper cousins buy the same shape by narrowing something: Disfigure hands you -2/-2 for two, Ultimate Price trades rate for a monocolored restriction, and other conditional kill spells fence the effect to a specific circumstance. What the extra mana buys here is reach, the ability to shrink a creature that two-mana removal simply cannot touch, and to do it on the opponent's turn. That makes it the unconditional edition of a conditional effect, and the mana it charges is the whole design argument: an answer that folds almost any single creature into the graveyard, no board state required, carries a steep tax, and that tax is what keeps the effect from crowding out its narrower, sharper siblings. It trades efficiency for certainty, and it knows exactly what it is paying for.