Spoils of the Hunt

A one-sided bite spell whose damage is bought, not fixed. Cast bare, the pump does nothing: your creature strikes with only its current power, enough to trade with something small. Feed it Treasure and every mana that comes off a cracked token adds another +1/+0 before the strike lands, so the more Treasure mana you funnel into the cast, the bigger the swing. That coupling is the design idea. Ordinary bite spells pay a flat rate for a flat effect; this one converts a resource you were already generating on the side into a scaling one-shot, gated specifically to Treasure rather than any ramp. And the damage is strictly one-sided: your creature hits, the target does not swing back, sidestepping the mutual-destruction gamble that makes true fight spells like Prey Upon a risk into a larger blocker. The instant-speed clause is what makes banking the Treasure worthwhile. Hold the mana, let an opponent commit a threat, then spend stored gold mid-combat or at end of turn for an exactly-lethal shot at the biggest thing they have assembled. It rewards a board where the Treasure was going to exist anyway, converting what would otherwise be flat removal into a burst that peaks precisely when your side has mana to burn.