Rally the Ancestors
A one-turn mass reanimation that immediately undoes itself: the instant timing and the self-negating exile clause are welded into the same line, and that welding is the whole design. Most reanimation pays for its power by being slow, single-target, or sorcery-locked; this inverts the bargain. It returns a graveyard's worth of cheap creatures at once, at any window, exiles itself as it resolves, then exiles the lot on your next upkeep. Read straight, that looks like the worst kind of reanimation: rent, not ownership. The X-or-less constraint scales the ceiling but caps the floor, so it rewards a graveyard stocked with small bodies rather than one fat threat. The upkeep exile is not really a drawback; it is a dare. The value has to come from the moment the army arrives, which is why it wants engines that cash a creature in on entry (an arrival trigger, fodder for a sacrifice-into-a-dies-payoff, a convoke or exploit cost that spends the body) rather than anything you plan to keep. Timing sharpens this further: the exile trigger goes on the stack at the start of your upkeep, before you draw and long before combat, so the payout has to be front-loaded onto the enter-the-battlefield event itself or onto a sacrifice you make in response, not onto attacks you may only get one swing of before they vanish. The instant window doubles as a wall of surprise blockers, with the upkeep exile clearing the board before anyone has to honor it long-term.
