Thunderheads

Defender plus flying is the whole point: this is a wall that arrives at instant speed, blocks a flier or three, and vanishes before it ever has to justify its presence as a permanent. The end-step exile is what lets the token punch above what a 3/3 flying blocker normally costs, since you never pay the long-term price of leaving a body on the board for an opponent to remove or punish. Replicate is the scaling lever that turns a single answer into a defensive line: pay the cost again and again at the moment of casting and you stack up enough sky cover to absorb an alpha strike, then let the whole flock evaporate. Blue has always wanted to interact reactively, on its own turn or the opponent's, without committing to a board it then has to defend; a flash-speed, self-cleaning blocker that multiplies on demand answers that pull neatly, trading the permanence other colors get for repeatability and timing freedom. The Weird creature type is mostly flavor (the elemental oddities of a blue-red guild), but the structural idea (a fog made of bodies rather than a single Fog spell) gives it a different texture: it actually blocks, it can chump multiple attackers, and replicate scales the wall to the threat in front of it.