Soul Foundry

Imprint turns a creature into a permanent factory, and the genius of the rate is that it scales backward: the cheaper the body you exile, the cheaper each copy. Lock in a one-drop and you are stamping out tokens for a single mana a turn; lock in something five-mana and you have paid a premium up front to amortize a finisher. That sliding cost is the whole engine, because it forces a real decision at the moment of imprint rather than at every activation. You commit to one creature's mana value the instant you exile it, and there is no taking it back. The exile itself is the cost that balances repeatability. Lose the Foundry and the imprinted card goes with it: no graveyard recursion, no second imprint, which keeps a four-mana artifact from quietly out-valuing every removal spell pointed at it. It rewards exiling a creature whose enters-the-battlefield trigger or evasive body is worth printing on demand, since the token is a genuine copy and brings every line of the original's text along. It was built as a slow value piece for grindy decks that wanted inevitability rather than a tempo play, and the design has aged into a recognizable template: pay once to choose, pay repeatedly to manufacture, and live with the choice.