Skred

Burn that grows out of your manabase, paid for with a deckbuilding tax most decks refuse to swallow. The damage equals your snow-permanent count, so in a deck running Snow-Covered Mountains as its land base, this is a one-mana instant that kills nearly anything by the midgame: a Lightning Bolt early, a Flame Slash a few turns later, then more or less arbitrary as the lands keep arriving. The price is real and lives entirely in the manabase. You swap basics for their snow versions, which do nothing on their own but tick the counter, and in exchange you get removal priced cheaper than its ceiling should allow. The trade is unusual on its own terms: snow as a mechanic normally exists to give activated abilities and cost reductions something to scale on, but here the scaling resource is the lands you were already playing, reskinned at no functional cost. Instant speed is what elevates it past a sorcery-rate point-removal spell, letting it answer a combat trick or kill a creature in response to an activated ability rather than committing on your own turn. It cannot reach players or planeswalkers, and that restriction is what keeps a one-mana spell of arbitrary size from becoming a burn deck's reach finisher: it is a creature answer, full stop, and a very good one in any red deck willing to commit its lands to snow.