Apocalypse Demon

A graveyard-fueled body with a meter running underneath it. The power and toughness scale with your bin, a design that rewards self-mill and aggressive trades, but the upkeep clause is what gives the card its tension: every turn you either feed it a creature or it taps out, useless for blocking and unable to swing. That turns the Demon into a recurring sacrifice tax, a creature that asks for a creature back every cycle just to stay active. The fantasy is obvious (a demon that devours its own followers to keep flying), but the structural job is to put your sacrifice fodder to work twice: once as graveyard fuel padding the body, again as the upkeep toll that keeps it untapped. Aristocrat shells that already generate tokens or chump bodies pay the tax without flinching; decks without that engine watch a huge flyer sit there inert. The flying matters because it makes the size relevant the moment you can afford to keep it untapped, converting a pile of dead cards into evasive damage. It is a finisher whose cost is paid in attrition rather than mana, a cleaner expression of black's bargain than most: the Demon is only as large as the resources you have already burned through, and only as useful as your willingness to keep burning more.