Mortal Combat

Twenty creature cards in one graveyard is not a count a deck stumbles into; it is a number you have to engineer toward, and that engineering is the entire archetype this card asks for. It belongs to a tradition of black build-around enchantments that reward treating the bin as something you load on purpose rather than fill through attrition, and the size of the threshold is what the cheap mana cost has to cost you. The win condition checks at your upkeep, so the clock is built in: assemble the twenty, survive one rotation, and the game ends on its own. Everything around it has to feed the yard fast, which is why self-mill, recursive chumps, and effects that dump creatures wholesale stop being nice-to-haves and become the structural spine of the build. The tension in the design is that the payoff is total (you simply win) but the setup is enormous and fragile: a single piece of graveyard hate resets the counter and erases turns of work in an instant. That fragility is the toll an alternate win this inexpensive has to pay, since four mana and a pile of dead creatures is the only entry fee it charges. It sits in the small family of "do this absurd thing and win outright" enchantments Magic prints to anchor a deck around a number, where the ceiling is a non-combat victory and the floor is a blank card in any list that did not commit to the count.