Pyroclasm

Two damage to every creature, and the number is the whole design. At two, this clears the floor aggressive decks build on (the one-toughness mana dork, the two-power beater, the token swarm) while leaving the format's payoff creatures standing. That asymmetry is the point: the player casting it usually has fewer or larger creatures, so a "symmetrical" effect lands lopsided in practice. It is the sorcery-speed ground reset that punishes a wide board without committing to a full board wipe, answering a swarm without surrendering your own threats the way a four-mana clean-everything does. The card has anchored a recurring red template ever since: cheap red sweepers tend to arrive priced against this damage-to-cost ratio, and most carry a restriction (a higher cost, a clause that spares your own side, a one-sided trigger) precisely because two damage to every creature for two mana already sits at the efficient end of what red is allowed. The discipline comes from the timing and the symmetry together. It resolves only on your turn, so it cannot ambush an attack the way an instant might, and it hits your own board as readily as the opponent's. The reward arrives only when you have built the asymmetry in advance, fewer or fatter creatures than the player across the table, rather than reaching for it as a reactive answer.