Whimwader

A 6/4 for five mana is an aggressive frame, the kind of body that puts a real clock on the table, and the design buys that rate back with a single contingency: it can only swing into an opponent who controls a blue permanent. The conditional is the entire transaction, and it cuts the opposite way from a hatebear. Most color-tax creatures punish the opponent for being on a given color; this one rewards you for facing it. Across the table from another blue deck, six power comes online and demands an answer in short order. Across from anything else, the card sits inert: a generously statted blocker that paid full freight for a body it can never point forward. This is mirror-tax design, and it rewires the deckbuilding question. You are not asking whether the body is good in the abstract; you are asking how reliably the table will be saturated with the color that unlocks it, which in blue-heavy fields is often enough. The four toughness is the catch on the other end. A five-mana investment that does not block cleanly trades down in mana against the cheaper four-power attackers it runs into, so the creature is conditional twice over: once on the opponent's colors to attack at all, and once on its own fragility to survive the swing. Few bodies make their playability so completely a function of who sits opposite them.