Serene Master

A blocker that weaponizes the attacker's own ambition. The body reads 0 power, so the Monk threatens nothing while it sits back; the payoff arrives only when it steps in front of something. When it blocks, the two creatures swap power values until end of combat, and because the Monk's base power is 0, the attacker is left swinging for nothing while the Monk inherits its number. A 6/6 charges in, becomes a 0/6, and eats 6 damage from the freshly minted 6/2; the bigger the threat, the deader it is. The arithmetic favors the defender because the swap happens on the declaration of blocks and resolves well before the combat damage step. First strike buys no escape: a creature reduced to 0 power deals 0 regardless of when it would deal it, so the exchange pre-empts the damage entirely. The catch is toughness. The Monk only kills an attacker whose original power is at least its toughness, so anything with toughness greater than power survives the trade: a 2/3 becomes a 0/3, takes 2 from the Monk's borrowed power, and lives. Square-statted bruisers and glass-cannon attackers die outright; durable midsize bodies walk away. The effect is purely reactive, punishing a single committed attacker per combat and punishing hardest exactly when an opponent overextends a big square creature into it. It reads like a riddle, but the instinct beneath it is old white: turn aggression into a liability, and let the size of the question set the price of the answer.