Floodchaser

The body is enormous for the cost, but it sits behind a clause most opponents will never satisfy on their own: it can only swing if the defending player controls an Island. The fix lives on the same card, and it eats the body to work. Each activation pays a blue mana and removes one of the six +1/+1 counters to turn a target land into an Island until end of turn, clearing the lane for combat at the price of a point of size. So unlocking the attack costs a counter every turn you want to do it, and the creature shrinks toward zero the more it does its job: a 0/0 with no counters left dies on the spot. The arithmetic is unkind. Six counters, one spent per swing into an Islandless board, plus the blue mana stapled to each conversion, means the clock counts down on itself. It is a design built around a single land-type payoff structure, where turning a land into an Island is the whole point and the body is just the resource you burn to do it. On paper it reads as a puzzle: a six-mana creature whose green light for combat is something you manufacture, repeatedly, out of its own toughness. In practice it is a liability that has to dismantle itself to function.