Slipstream Serpent

The whole design is a joke about Islandwalk turned inside out. Where a creature with Islandwalk wants the opponent to be the blue player, this Serpent demands the same condition just to swing at all, then punishes you for being the blue one: lose your last Island and it dies on the spot. That second clause is the genuinely cruel part, because the body is enormous (a 6/6 is a real clock in a color that struggles to build one), but it ties its own survival to a land type you may need to fetch, trade away, or watch get blown off the table. Morph is what makes the package coherent. Cast it face down for three and it is just a 2/2, free of the Island leash; the unmorph turns it into the big Serpent only when you have decided the board texture is right, and only then do the attack restriction and the suicide clause switch on. It is a card built around bluffing and timing rather than raw rate: the cheap face-down body buys tempo, and you choose the moment to commit to a creature whose two conditions both cut against the controller as readily as the opponent. The flavor read is clean too, a sea monster that can only menace coastlines and beaches itself the moment the water dries up.