Marsh Casualties

A one-sided sweeper that scales with the game. Two black mana hands an entire opposing battlefield a -1/-1 in the mold of Shrivel or Nausea: enough to clear a swarm of tokens or a one-toughness aggressive curve-out before it gets rolling. Hold the spell, pay the extra three, and the same card upgrades to a -2/-2 wipe that catches the two-toughness creatures the unkicked version leaves standing. The design is clean because it never wastes itself: the early-game answer and the mid-game answer live on one card, and you pay for the bigger one only when the board demands it. Pointing the effect at a single player rather than every creature is the restriction that makes it asymmetric, so it works as removal aimed across the table while your own board stays untouched, rather than as a true sweeper cast from behind. That asymmetry sets it apart from the symmetric -X/-X wipes black usually pays full price to cast. The cost of pointing it sideways is its ceiling: even fully kicked it only kills creatures with two or less toughness, so it answers a board built wide and low and does nothing to one built tall.