Overeager Apprentice

Three black mana out of a one-time, three-mana body, with the catch that you pay for the conversion twice: once in the card you pitch, once in the creature you lose. That trade is the entire design. This is a ritual stapled to a sacrifice cost, built for an early-era graveyard economy where filling the bin fed engines rather than emptying your hand for nothing. The discard feeds flashback, threshold, and madness, so the apprentice does not just generate mana, it loads a graveyard while it does it, and the body itself goes there to count toward threshold once it has served. The math is its own restraint: paying three to add three nets zero on the turn it is cast, so the burst it produces is not raw acceleration but color fixing and a quality conversion (a dead card and a spent body traded for triple black at the moment you need it). The cost it cannot dodge is card disadvantage: every activation puts you down a card and a creature for a single mana spike. It rewards decks that already wanted a card in the yard and punishes anyone treating it as a generic mana rock. The lineage runs through Dark Ritual and its imitators, but where those spend one card for a one-shot burst, the apprentice asks you to spend two permanents-worth of resources and treats the discard as an upside rather than a price.