Traxos, Scourge of Kroog

Seven trampling power on a four-mana body is a rate that should warp a format on its own, and the entire design exists to claw that number back. The drawback is unusually punishing: not vigilance-style "stays tapped after attacking" but a creature that arrives tapped and never sees its own untap step, so left to its own devices it does nothing forever. The untap clause is the engine, and it ties the body to a specific kind of deck. Casting a historic spell (an artifact, a legendary, a Saga) snaps it upright, which means every turn you want to attack you must also spend a card from a fairly narrow band of the cardpool. That is the genuine cost: not mana, not life, but a deckbuilding contract that forces an artifact-and-legendary density most lists would never run. What makes the design clever is how the untap timing works. The trigger fires on cast, so a historic spell during an opponent's combat or end step readies a 7/7 blocker, and a historic spell before your own attack turns the body live without waiting for a sorcery-speed window. It punishes the synergy-free deck and rewards the one built around it: the rare big-creature drawback that is fixable purely through construction rather than through a separate untapper or a vigilance grant bolted on after the fact.