Soulblast

The whole board, cashed in for one number. This is the rare burn spell whose damage output is not printed anywhere on the card: it scales to the total power you sacrifice, which means the spell does nothing without a board and everything with a big one. The additional cost is the design's entire balancing act, and the instant timing is what keeps that cost from being prohibitive. You can let your creatures attack, watch combat resolve, and only then fold the survivors into a face full of damage during the second main phase or the opponent's end step. You can also declare blockers, then sacrifice those blockers to Soulblast before combat damage is dealt: the attackers still bounce off the chump-block, and the power that was about to die in the red zone becomes burn instead of a trade. That flexibility is the wrinkle that makes the rate work, because it lets the same wide board play defense and threaten lethal in the same turn. The strategic identity is a finisher for go-wide token strategies, where a swarm of small bodies that individually accomplish little converts, at instant speed, into a single lethal bolt or a sweep through a key creature. It is the sacrifice-payoff impulse that drives aristocrats decks, expressed not as a grinding engine but as a one-shot: everything you have built, spent at once, for a guaranteed total.