Outbreak

Discard a Swamp from hand and the sweep costs no mana at all, a tempo-neutral answer that lets a mono-black deck shave a board state without ever tapping out. That trade descends from a pitch-a-land cycle where each color got a spell payable by discarding the corresponding basic, an early-era attempt at decoupling the effect from the curve. The catch sits in the math. Minus-one-one to a chosen creature type is a narrow knife: it kills tokens, mana dorks, and small tribal aggressors en masse, but the moment a board carries anything with two toughness the sweep glances off harmlessly. So it answers one specific shape of opponent, the wide-and-fragile tribal swarm, and pays for that narrowness by demanding a Swamp you would often rather keep for a land drop. Choosing the type on resolution buys a sliver of flexibility (you name what is actually in front of you, not what you guessed in advance), but it stays a sorcery, with no way to ambush a combat step or punish an attack mid-stack. The honesty of the design lives in how the pitch cost and the toughness ceiling were tuned against each other: a free board wipe that only ever shaves a single point of toughness. The free spell is the reason the ceiling has to be so low, and the low ceiling is the reason the spell can afford to be free.