Withering Wisps

A pinger that scales with your snow Swamps, gated by a resource the rest of the world ignores. The activation cap keys off snow Swamps specifically, not Swamps in general, which ties the card to Ice Age's snow-permanent subtheme and turns land-type counting into a throttle on how fast you can grind the board down. Each ping is symmetric, hitting every creature and every player including you, so the card is built as a controlled bleed rather than a one-sided sweeper: you spend mana per point, you take the damage too, and the ceiling on activations per turn is whatever your snow Swamps can support. The self-sacrifice clause is the cleanup discipline. With no creatures on the battlefield at end step it falls off on its own, which keeps an open-ended damage engine from becoming a permanent fixture that grinds out solitaire wins after the board is already empty. As a black answer to swarms of small creatures in an era before black had clean repeatable sweepers, it is paid for in life and in the friction of needing the right snow lands online. Ice Age leaned on land-subtype payoffs as a balancing lever, building power that only the player who committed to the subtheme could fully access; this is that lever applied to attrition, where the engine's throughput is rationed by how deeply you have bought into snow.