Momentous Fall

The instant-speed window is the whole engine. Green has long had cards that turn a creature into cards, but most ran at sorcery speed and asked you to commit the creature before the dust settled. Casting this in response to removal converts a dying creature into its full power in cards plus its toughness in life, so it both answers the spot-removal that would have stranded your investment and rewards you for building a fat body to feed it. The math scales with the creature, not the spell: a modest attacker draws a couple and gains a little, while anything you have spent real mana pumping cashes out for a windfall. That places it in a small green lineage of "draw equal to power" payoffs, where the design tension runs between drawing big and surviving long enough to do it. The additional sacrifice cost is the ballast against a free refuel: you are always down a permanent and a card, betting that what comes back exceeds what you spent. It works best alongside creatures that already want to die (a death trigger turns the sacrifice into a second payoff) and token-makers that can spare a large body without surrendering the board. The life gain is the quiet half, but against an aggressive draw a high-toughness sacrifice can swing a race as hard as the cards do.