Shape Anew

Polymorph for artifacts, and the conversion math is the entire sell. You spend four mana to swap a worthless artifact you already control for whatever sits on top of your deck, so the spell answers to deck construction rather than luck: run a single fat artifact, fill the rest of the spell slots with anything that is not an artifact card, and the random reveal stops behaving as random. The sacrifice clause is the toll. You have to surrender a permanent to feed it, which means the cheapest possible body (a Servo, a Thopter, a Treasure spat out for one mana) becomes the engine's real cost. Read closely, the dig is a deckbuilding constraint disguised as a guarantee: it reveals until it hits an artifact, not a permanent, so a stray cheap artifact in the maindeck can cheat out a do-nothing instead of your payoff. Get the ratios right and the reveal is deterministic; get them wrong and you flip a Mox into play and waste the turn. Shape Anew sits alongside Polymorph, Proteus Staff, and Transmogrify in the line of effects that ask you to engineer your own probability instead of trusting it. The distinction is the resource it eats: where its creature-targeting cousins demand a token body, this one can consume a manufactured artifact you would have produced anyway, which makes the enabler trivial to assemble and the spell far easier to set up than the four-mana rate suggests.