Skittering Crustacean

Most monstrosity creatures spend their mana to get bigger; this one spends it to buy protection. The seven-mana activation does the usual counter math, turning a 2/3 into a 6/7, but the payload is the hexproof clause that switches on the moment it goes monstrous. That reframes the whole card: it sits on the board as an unassuming early body, declines to commit, and then on a turn you can spare the mana converts into a threat opponents can no longer point removal at. The cost structure is the discipline keeping it fair. Seven mana to flip is steep enough that you rarely race to it, and until then the creature is a plain 2/3 holding an ability it hasn't paid for, exposed to anything that wants it dead. The hexproof is narrower than it looks, though, and that is the honest part of the design: it only stops targeted spells and abilities, so once the counters land opponents can still trade in combat, wrath the board, edict it away, or answer it with any effect that doesn't need a target. What the flip buys is immunity to spot removal, not invulnerability. It is a slow card by design, built to outlast a board stall rather than break one open, the kind of patient blue win condition that wins by refusing to die to a single card.