Tree of Perdition

The trick is inversion: a Plant that never deals damage but resets an opponent's life total to its own toughness, slamming twenty down to thirteen in a single tap. That is a discount, not a kill, and the rest of the design is the puzzle of turning thirteen into lethal at your own pace. Once the swap resolves, the work shifts to grinding the opponent's new, fixed life total down: a repeatable drain, a recurring point of damage, anything that subtracts from a flat number is suddenly closing the game far faster than chipping away at twenty would. The Defender keyword is the honest cost of that power, a body built to stall while the activation does the only offense it owns. Note the swap runs both ways, so against a fast deck that has already pushed itself low, the exchange can hand the opponent life back; this is a creature for a patient, attrition-minded plan, not a tempo race. It shares its win condition with black's other numbers-rewriting walls, trading the usual question (how much can I deal?) for a stranger one (how cheaply can I subtract from a total I just imposed?). The 0/13 line reads like pure defense, but the toughness is really ammunition: the thirteen it stamps onto the opponent is a ceiling you spend the rest of the game lowering.