Dead of Winter

The scaling clause is the whole engine here: a board wipe whose size is set entirely by how much snow you've bothered to assemble, and one that costs the same three mana whether it kills a swarm of tokens or fizzles into a -1/-1 shrug. That conditionality is the price. Symmetric-looking sweepers usually pay for their flexibility with a fixed number or a life cost; this one demands a snow-heavy manabase built up front, then rewards the investment with a wrath that spares your snow creatures, since snow creatures dodge the effect entirely. The nonsnow qualifier is doing double duty: it exempts your snow creatures while punishing an opponent who never opted into the snow subtheme, which most decks don't. It sits in a small lineage of snow-matters payoffs that revived a mechanic left largely dormant for years, and among them it's the one that turned snow from a color-fixing curiosity into an actual deckbuilding tax with a real reward at the end. The catch is that the reward tracks the setup exactly: with a thin snow count it's a dead card, and since -X/-X only lowers toughness by your snow total, anything currently tough enough survives the pass. It is the rare removal spell whose ceiling and floor are both fixed before the game starts, by how far you were willing to commit to a mechanic most players ignore.