Weigh Down

A single black mana buys a -3/-3 shrink, but only if you have a spent creature in the graveyard to feed to exile: that clause is the entire equation, and it turns a removal spell into an economy question. Decks that fill the yard fast (self-mill, aristocrats, anything that trades creatures early and often) treat the exile as free, because those cards were never coming back to the battlefield anyway. Decks that lean on recursion, reanimation, or a thin creature count feel it as a genuine tax, sometimes an uncastable one. That asymmetry is the design's point. At one mana, an unconditional -3/-3 would be reckless; the exile clause both prices the effect and steers it toward the graveyard-hungry strategies where cheap, permanent creature-shedding is a resource rather than a loss. As a sorcery it kills nothing bigger than three toughness on its own and answers threats only on your own turn, so it reads as attrition tech, not a catch-all. The subtler wrinkle is that exiling from your own graveyard doubles as self-inflicted graveyard denial: you are spending future recursion fuel to solve a present threat, a trade that rewards decks with more bodies than they know what to do with and punishes decks counting on every card in the yard staying there.