Contagion Clasp

Proliferate's most honest ambassador: a colorless artifact that opens with a targeted payload, then becomes the engine that lets every counter on the board grow. The entry trigger does real work on its own, shrinking a one-toughness blocker or finishing off a creature already weakened, but the body of the design is that activated ability. Four mana and a tap is a steep price for a single proliferate, which is precisely the restriction that keeps the card from being a runaway engine: it cannot multiply counters faster than your mana allows, so the snowball is paced rather than explosive. What makes the proliferate clause matter is its indifference to counter type. It does not care whether the counters are -1/-1 markers on enemy creatures, +1/+1 on your own, loyalty on a planeswalker, charge on another artifact, or poison on an opponent. Each activation advances every clock simultaneously. The card was built in an era when counters had quietly become a unifying currency across colors and card types, and its job is to be the colorless lever any deck can pull to compound that currency. The -1/-1 counter on entry is not incidental flavor; when it lands it seeds the board with something to proliferate immediately, giving the engine early fuel. A patient, repeatable threat-and-engine in one slot, priced so that patience is the cost of admission.