Wildsize

Trample is what turns this from a forgettable pump spell into a card worth running. A combat trick that can stop a chump block, push damage past a wall, and replace itself in hand is doing three jobs for one card, and that extra evasion keyword is doing most of the heavy lifting. Cast in response to a block from a smaller creature, it converts a stalled attack into face damage; the cantrip means it never costs you a card even when the pump alone fails to generate a two-for-one. The replacement clause carries the real design logic: green's earlier combat tricks asked you to gamble both tempo and a card on a single ambush, while this one removes the downside by letting the spell pay for itself. The practical effect is a trick you can run more freely than its size suggests, because the worst case is a card swap with a small board boost attached rather than a dead draw. It belongs to a line of green instants built to make the combat-trick slot safe to maindeck, designs that want a body worth protecting and an opponent willing to block into open mana.