Mausoleum Guard

Death is the only thing that pays out here; until then, four mana buys a 2/2 holding a coupon it cannot redeem. The transaction is the trigger: trading the body away, walking it into combat, or sacrificing it to fuel something else cashes out into two flying Spirits that together outsize what was lost. That asymmetry rewards aggression rather than punishing it. Blocking it profitably is hard when the attacker comes out ahead on the swap, and chump-blocking with it leaves two evasive bodies behind. The split into two tokens is what makes it more than a single replacement creature: it feeds anything that counts creatures hitting the graveyard or wants a wide board of fliers afterward, from convoke and sacrifice payoffs to anthem effects to two fresh equipment carriers. Spirits-with-flying is a recurring white token mold, but most printings hand them over at a steeper cost or with an upkeep tax; this one front-loads nothing and back-loads everything, asking only that the original creature actually die before it pays. That dependence on death is the cost. Against an opponent who refuses to engage in combat and has no removal worth spending, the Guard simply stands there as a plain 2/2, the payout stranded until something kills it.