Polymorphous Rush

Most copy effects point at one creature and ask you to find something worth becoming; this one inverts the math, turning your whole board into copies of any single creature on the battlefield at once. The scaling cost is what keeps that workable: the base price is cheap, but every extra creature you transform demands another , so the spell asks more the more committed you are to the play. The real flexibility hides in what the spell actually targets. Your own creatures are the targets; the creature being copied is only chosen, not targeted, which means an opponent's hexproof or shrouded bomb can still serve as the template for your entire team. The "until end of turn" clause leaves the effect sitting at the seam between a defensive combat trick and an offensive alpha strike. Copy a wall before damage and a swarm of tokens survives an attack it had no business surviving; copy a beater after blocks are declared and that same swarm trades into a board of fatties. Instant speed is what makes the effect dangerous rather than a curiosity: you commit nothing about the play until the combat math is on the table, then you rewrite it. It reads like a build-around, and it is one, but the deck it wants is just a wide board plus one good copy target, which plenty of creature decks already field without trying. It converts quantity into quality on the stack, priced so that the more board you have, the more it asks and the more it pays.