Wave of Terror

A timer that sweeps the board in widening rings, with the age-counter clock doing double duty: it is both the cost that drains your mana every turn and the dial that selects which slice of creatures dies at your draw step. The first tick clears one-drops, the next clears two-drops, and so on up the curve, so the card walks through the cheap end of the battlefield before it threatens anything expensive. That ascending targeting is the design's clever cruelty: it punishes go-wide aggression early, when the counter is low and the upkeep is cheap, then becomes prohibitively expensive to maintain right as it would start hitting the fatties. The symmetry is total (it destroys each creature at the selected mana value, yours included), so building around it means leaning on tokens, whose mana value is zero and so sit below the rung the counter ever reaches, creatures already off the relevant slot, or simply outpacing your own scythe. It belongs to that early-design school of enchantments that automate a board state at a steadily rising tax, a structural cousin to the other cumulative-upkeep permanents that asked you to commit mana to keep a machine running rather than cast a one-shot. The reward for paying is a repeatable, regeneration-proof wrath that you, alone, get to schedule.