Retribution of the Ancients

The black half of a mechanic that asks you to treat +1/+1 counters as ammunition rather than permanent stat boosts. Pair this with an outlast deck or any source that piles counters onto your team, and the counters stop being insurance against combat math and start being a repeatable, untapped removal engine: pay one black, strip counters from your own board, shrink something on the other side. The conversion runs in your favor when you have spare counters and a target worth killing, but the cost is brutal in the abstract, since every point you spend is a point of power and toughness you are subtracting from your own creatures. The repeatability is the whole appeal: there is no per-turn limit, so a board flush with counters can answer a sequence of threats or sink everything into one oversized kill in a single turn at instant speed. Because you can hold up the activation and let the opponent commit before deciding whether to spend, it plays as a reactive tool rather than a one-shot removal spell. The design problem it solves is what to do with counters that have already done their job, turning a static buff into a flexible resource. The tension that keeps it from running wild is the self-cannibalizing math: you are always trading your own board's size for the privilege of shrinking theirs, and the engine only hums when something else is constantly refilling the tank.