Metamorphic Blast

Spree is the mechanic that keeps this off the cut pile: with no default mode and a single blue mana as the entire base cost, the card prices itself as the sum of whatever a board state actually demands. Pay one extra and a threatening creature becomes a 0/1 for the turn: not a kill, but a Pongify-style shrink that leaves a body behind, which matters when the opponent has a death trigger you would rather not hand them. Pay three extra and a player draws two. Pay both, and one instant answers a blocker and refills a hand in the same window. Neither mode would earn a slot at those rates on its own; the shrink is a soft answer with an expiry date, the draw expensive against dedicated card advantage. What redeems both is that Spree lets the card float to whichever floor the turn needs, and only asks for the mana once the job is known. The honest limitation is the "until end of turn" clause on the shrink: it buys a combat step or dismantles an attack, but the creature snaps back to its printed stats afterward, so this is tempo and disruption, not permanent removal. The white Rabbit framing is a flavor wink layered over the real point, which is a modal instant engineered to refuse dead weight in any line.