Skeleton Shard

Mirrodin's artifact-matters block needed a recursion engine that respected what it was recurring, and this is the answer: a colorless artifact that buys back artifact creatures specifically, with a flexible cost that lets either tapping itself plus three generic or tapping plus a single black do the work. That dual-payment design is the clever part. The black option makes it a natural fit in artifact-aristocrat shells that want to sacrifice and rebuy cheap robots, while the all-colorless option keeps the door open for decks running no black at all, leaning on generic mana to fuel the loop. What it builds toward is a grind that does not care about color identity at the floor but rewards it at the ceiling. Pair it with any artifact creature that carries a death trigger or a sacrifice-for-value clause and you have a repeatable engine that turns the graveyard into a holding pen rather than a final destination. The activation only returns to hand, not directly to the battlefield, so it asks for a mana investment twice over: once to retrieve, once to recast. That tax is the friction that keeps it from spiraling, and it pushes the card toward decks with enough mana to do both in a turn or enough patience to do it across several.