Mistwalker

Four toughness under a flying body makes this an awkward thing to swing into: it walls the air, soaks up early evasive damage, and buys a slower deck time to set up. The activation is where the wall reconsiders itself, shaving down toughness to add power each time it fires, so the same blocker that held the sky can lean forward into a patient clock once the game turns. Every push toward 4/1 erodes its own survival, keeping the decision live turn to turn: sit at 1/4 and keep the air closed, or spend down toward lethal above the ground. Changeling is what ties the package together: a modest flier that reads as all creature types at once benefits from any lord, feeds any type-matters payoff, and answers any "choose a creature type" clause without committing to one tribe. A Shapeshifter in a type-based shell earns its slot by being whatever the roster is short on, and this one stacks flying and a self-contained growth switch on top of that flexibility. It plays as three things wearing one face: an air defender, a slow evasive threat, and universal tribal fodder that slots into whichever type synergies happen to be in play.