White Sun's Twilight

An X-spell that answers two different questions depending on how much mana you pour into it. Below five, it is a lifegain-and-swarm play: a pile of poisonous bodies that chip in toward an alternate win condition rather than the twenty-damage clock, with the life buffer to survive the turns it takes to close. At five and up, the same card becomes a one-sided sweep, leaving your fresh Mites standing while everything else dies. That threshold carries the design's whole tension: the wrath is stapled to a board you built the same turn, so the cost of the mass removal is also the payment for the army that outlives it. The toxic 1 on the tokens ties the card to poison as a parallel damage system, where each unblocked hit advances a ten-counter clock instead of the standard life total, and the tokens are barred from defense so they stay pure offense rather than a wall. That makes it a rare white sweeper that does not reset you to parity: you cast it, you clear the board, and you are the one left with creatures and a life cushion. The scaling means the card reads differently at every point on the curve, and the destroy-all clause switching on at X of five gives it a natural inflection where a value play becomes a haymaker.