Heat Stroke

A combat-step punisher built around the one decision every attacker and blocker makes anyway. The enchantment sits on the board doing nothing until creatures meet in combat, then taxes the interaction itself: anything that blocked or was blocked dies at end of combat, regardless of how the damage shook out. The design discipline is that it cares about participation, not outcomes, so a brick wall that survives the exchange dies anyway, and a tiny blocker can trade up into something enormous. That makes it a deterrent more than a removal spell. Once it resolves, attacking into an untapped board becomes a question of which creatures you are willing to lose, and blocking becomes a way to throw away two cards at once. The trade-off is symmetry: the enchantment does not read your colors or your intentions, so it punishes your own combat math as readily as the opponent's. That hands the advantage to whoever can win without committing creatures to the red zone (burn, evasion, pingers that sit back) and turns the card into a wall-of-Damocles that reshapes the combat step from a place where creatures fight into a place where they refuse to. It belongs to red's old "combat is a trap" design language, where damage-doublers and combat-trick enchantments turned the red zone into a hazard rather than a battlefield; here that instinct hardens into a permanent that makes every block a potential extinction event.