Corrosion

A clock built backward from how artifact decks actually function. Most artifact hate kills one target now; this kills everything eventually, on a delay that accelerates. The rust counters accumulate each of your upkeeps, and an artifact dies the moment its mana value falls at or below its counter total, so the cheapest pieces (Mox-style mana rocks, one-drop utility) crumble first while the expensive bombs hold out for a few turns. That staggered timing is the whole design: it punishes the broad, cheap-artifact builds that lean on quantity rather than a single haymaker. The trade Wizards extracted for an effect this sweeping is cumulative upkeep, the period's preferred governor on open-ended permanents. Each turn it sits on the battlefield costs more mana to maintain, which means the same engine that grinds opposing artifacts to dust is also grinding your own resources; left to run, it eats you before it finishes the job. The leaves-the-battlefield clause that strips all rust counters is the safety release, ensuring the corrosion only progresses while you keep paying for it. It is a piece of the era's enchantment-as-attrition-engine school, where the power was real but rented, and the design discipline lived entirely in the upkeep tax rather than in the rate on the rest of the card.