Nausea

One point of toughness reduction draws a precise line through the battlefield: everything with a single point of toughness dies, everything bigger walks away clean. That floor is the entire design. Black has never lacked cheap edicts or creature-targeted removal, but a true blanket sweeper at this cost only stays honest if the reduction is small enough to be self-limiting; one point clears the swarm of tokens, mana dorks, and weenies while leaving anything the opponent actually paid for untouched. It rewards a deck built to fight go-wide aggression rather than midrange, and the fact that it kills your own one-toughness creatures too is the tax that keeps the rate fair. The card sits at the smallest rung of a ladder of toughness-reduction sweepers: Infest doubles the reduction to -2/-2 and catches a wider band of bodies, while a true wrath like Damnation ignores toughness entirely and resets the board outright. Each rung up costs more mana and gives up the surgical precision that defines this one. Its identity lives entirely in being the cheapest, fastest version of "punish a board you can count on your fingers," and in accepting that everything taller than a single point of toughness survives.