Galvanic Iteration

Any spell-copy effect costs a card and a turn's worth of setup to do nothing on its own; the copy has to land on something worth doubling before the investment pays. Flashback is what earns back the tempo hit: the copy engine reloads from the graveyard, so a single window of doubled instants and sorceries becomes two windows across two turns, or one enormous turn where both castings fire before the payoff resolves. Cast this, cast it again from the graveyard, then cast one instant or sorcery: it copies twice, and if that spell is a burn spell, a mill effect, or a life-drain, the multiplier climbs fast. The "when you next cast" phrasing is the load-bearing restriction. The doubling is deferred and one-shot, so you cannot bank it or aim it retroactively; you commit to copying the next spell you cast, whatever it is, and the sequencing has to be exact. It names instants and sorceries specifically, never permanent spells, so the copy chooses new targets and resolves as a spell that ceases to exist rather than leaving anything behind. That places it in a lineage of prowess-adjacent, storm-adjacent copy pieces built to reward a deck that chains cheap spells rather than deploys one big threat. The reusable second cast is the wrinkle: earlier one-and-done copiers spent themselves on a single window, while this one buys a rematch.