Ore-Rich Stalactite // Cosmium Catalyst

Craft is one of the few mechanics that spends your graveyard as a resource rather than replaying it, and this card weaponizes the tension between its two faces cleanly. The front half is a mana rock on a leash: it taps for a single red mana usable only on instants and sorceries, so the deck it wants is one that casts spells constantly and stockpiles them in the yard. That stockpile is the fuel. Once you have four or more red instants and sorceries buried, the craft cost exiles them to flip the artifact, and the payoff on the back reframes what you gave up. Cosmium Catalyst does not hand those cards back all at once; instead it lets you cast one at random for free each turn from that exile pile, turning a heap of spent spells into a slow free-cast engine. The randomness is the honest part of the bargain: you traded control of your graveyard for a lottery, and a good build stacks the odds by exiling four spells that are all worth casting rather than one bomb and three duds. The catch is depletion: each activation lets you cast the actual card, so it resolves into your graveyard and leaves the exile pile, and the machine fires only as many times as the number of cards you buried to build it. It reads the spellslinger's habits back to them, then puts a hard clock on the payback.