Shadowblood Egg

The interesting thing about a mana rock that wants to die is that the dying is the point. As one of five eggs in a cycle, this one filters generic mana into a specific two-color pair, replaces itself with a card, and then leaves the battlefield entirely, which in a graveyard-centric era was a feature stacked on top of a feature. Sacrifice it and you have fixed black and red, smoothed your next draw, and added an artifact to the bin in a single motion, feeding any deck that profited from cards arriving in the graveyard. The restraint is in the cost structure: you pay one to cast it, then two more and a tap to crack it, so the mana it eventually produces is never the free acceleration a true rock offers. That is the bargain the cycle strikes. It does not ramp; it converts time and a card slot into color fixing plus a self-replacing graveyard contribution. The result is a builder's piece, designed for decks that want artifacts hitting the yard and want to draw through themselves, where the activation tax is repaid by everything that happens around the sacrifice rather than by the mana itself.