Fury of the Horde

The seven-mana sticker price is a deliberate fiction. Nobody casts this for mana; the alternative cost (exile two red cards from hand) is the live line, and the printed mana value exists to give the spell a number, not a plan. What you actually buy is a second combat phase that untaps everything that already swung, the kind of effect that does nothing in a fair deck and ends the game in an unfair one. The math is brutal once your board is wide enough or your attacker hits hard enough: double the damage in a single turn for the price of two cards you can spare from hand. This is combat-step extension folded into a deck's resource math rather than its mana base, in the lineage of free spells that pay themselves out of card advantage. The exile clause is the governor, and it bites twice: a pure red shell can stock its hand with burn and creatures as fuel, while any deck splashing red has to ask whether it can give up two on-color cards at the exact moment it wants to alpha strike, and those cards leave the game entirely rather than feeding a graveyard. That tension (the cards you exile are the cards that made the attack worth doubling) is what keeps the effect from being trivially repeatable, and it is why the spell lives in dedicated builds rather than as generic reach.