Rook Turret

A flying body that doubles as a filtering engine, keyed to a trigger every subsequent artifact deployment turns on. Each artifact that follows draws you a card and then asks you to pitch one, digging you toward what you want while you build a board. This is looting, not rummaging, and the order matters: you draw first, so an empty hand is no obstacle and the discard clause becomes a way to bin the card you just drew rather than a wall you cannot pay. That structure asks for a deck packed with cheap artifacts, so the trigger fires again and again across a turn cycle rather than resolving once and going quiet. The discard clause is the pivot everything else rotates around, not a tax to route around: it converts dead lands and situational answers into live cards, and it feeds graveyard payoffs, delve and flashback spells, and reanimation targets you would rather bin than draw off the top. Because the trigger is optional, you leave it dormant when your hand is already humming and switch it on when you need to dig. The 3/3 flier keeps the card relevant while the artifacts are slow to arrive. The check on the design is that a resolved copy does nothing extra by itself and needs a stream of artifacts to earn its blue mana and four-mana price. Read carefully, this is card selection dressed as card advantage: you swap the cards clogging your hand for the ones you want, one artifact at a time.