Scute Swarm

The sixth land is the switch. Below it, this is a modest token engine, spitting out a 1/1 Insect per drop; at six lands the ability flips from making tokens to copying the whole creature, and every land after that doubles the board instead of adding to it. That single conditional carries the entire design, and it is doing something rules text rarely commits to: geometric growth. Cross the threshold with two Scute Swarms in play and a land makes two more; the next land makes four; a fetchland or an extra land drop compounds it mid-turn. The 1/1 body is deliberately inert, because the card is not asking to attack for value: it is asking you to keep resolving lands until the token count stops being countable. What holds it down is the same thing that powers it: it needs lands, in volume and in sequence, so a stalled draw leaves a lone Insect doing nothing while a flooded one wins on its own. That tension between the worst topdeck in the deck and "the game is over now" lives entirely in whether the sixth land arrives. It is a rare instance of a common-sized creature whose ceiling is genuinely uncapped, held down only by how many lands one player can physically put onto the battlefield.