Skyshaper

The design logic is the sacrifice clause: this artifact has no recurring value, nothing to do until you decide the game ends this turn. That all-or-nothing structure is what keeps a colorless, two-mana mass-evasion effect from being oppressive: you pay for it twice (mana up front, the permanent itself on the way out), and the window is a single combat step. The payoff scales with how wide you are, which makes it a finisher for go-wide strategies rather than a midrange utility piece. Granting flying to the whole team at instant speed cuts both ways, too: the same effect that turns a gummed-up ground stall into a lethal alpha strike can be held back to give your ground creatures sudden reach, an emergency blocking button against an incoming flying assault. It sits face-up, so the opponent knows the trick is available; what they can't predict is the turn you decide to spend it. The colorless cost is the quiet part of the design: any deck that can curve into a token swarm or a small army of bodies can slot it without bending its mana, a wider net than a green or white overrun-style card casts. What it asks in return is patience and a board worth sacrificing for, since the artifact does nothing on its own and gives the opponent no reason to react until the combat math is already settled in your favor.