Harbor Serpent

The conditional attack clause is the whole bargain here: a 5/5 body sits inert, forbidden from attacking until five or more Islands are on the battlefield, and that count pools both players' lands. In a mirror of blue decks the threshold arrives sooner, and the islandwalk that rides along converts a satisfied attack condition into an unblockable swing against the very opponent whose Islands helped fill the quota. The design tries to make a heavy mono-blue commitment feel like a reward rather than a tax: lean blue enough to support a double-blue six-drop, and the early-game dead weight comes online late as a finisher the right opponent cannot stop. The trouble is that the two clauses pull in opposite directions. The five-Island requirement asks you to wait; the islandwalk asks for an opponent who also plays Islands, which the wait does nothing to secure. When both line up it is a clean evasive top-end. When they do not, you are paying six for a 5/5 that cannot attack at all until the count is met, though even a stranded one is still a perfectly serviceable ground blocker, which softens the downside considerably. This is an early-era take on the conditional fatty: a creature that names exactly what kind of game it wants to be in, and is candid about having little to do anywhere else.