Downsize

Most defensive spells subtract toughness; this one subtracts power, which is the more honest way to neutralize an attacker and the more frustrating one for the opponent. A creature dropped to -4/-0 keeps its toughness, so it survives the turn and the blocks, but its incoming damage either vanishes or shrinks to nothing. As a one-mana instant, that buys a clean turn against a single threat: a fat finisher bounces off a chump for free, a lethal attack stops being lethal. The overload mode is what justifies the slot, turning a one-target Fog-with-a-knife into a board-wide power wipe at instant speed for three mana. Cast that during a declared attack and every creature the opponent controls loses four power at once, which can blank an entire alpha strike without killing anything or touching the board state on your side. The trade the card makes is that it never removes a threat; the creatures live, and next turn they hit at full strength again. That ceiling keeps it as a tempo-and-combat trick rather than an answer, a spell that wins the exchange in front of you rather than the game. Overload is the mechanic that lets it scale from a surgical one-mana parry to a one-sided combat reset without printing two cards to do it.