Mausoleum Wanderer

The activated ability is where this flyer stops being a body and becomes a piece of protection, because the tax it levies scales with the exact board development that powers the deck around it. It counters an instant or sorcery unless the opponent pays mana equal to its current power, and that power climbs every time another Spirit lands. Hold it back, drop two Spirits in a turn, and it is suddenly demanding a three-mana tax (or a flat counter if they cannot pay) at the precise moment the opponent is trying to sweep the board or resolve a key spell. Because the sacrifice costs no tap and no mana, the two jobs are not mutually exclusive: it can attack during combat and still be sacrificed later in the same turn to answer a response, functioning as both a clock and the insurance policy on that clock without forcing a choice. Flying Spirit aggro existed before this kind of one-drop, but bolting a soft counterspell onto the cheapest slot in the tribe let it protect its own development instead of simply racing. That single-color disruption gave the archetype a tempo axis it had lacked, and the power-scaling counter is the load-bearing piece of the shift: the same triggers that pump the body also raise the price of interacting with the whole game plan.