Contagion Engine

Most proliferate cards multiply counters you already have; this one manufactures the counters first, then doubles down on the multiplication. The enter trigger lays a -1/-1 counter on each creature a target player controls, which against an opponent reads as a one-sided sweep of tokens and a softening blow against everything bigger. The activated ability is where the design turns greedy: proliferate twice in a single payment, so the same battlefield state advances two steps for the price of one. That second proliferate is the structural divergence from every other counter-multiplier in the line. A single proliferate adds one more -1/-1 counter to each wounded creature, finishing off the survivors; firing it again the same turn pushes the kill threshold up another notch, and on planeswalkers or charge-counter rigs it ticks loyalty and storage at double rate. The colorless cost is the decision that matters most: any deck trafficking in counters at all (poison, +1/+1, charge, loyalty, anything that increments) can run it without a color commitment, which is why it lands as a payoff in proliferate shells rather than a role-player. The entry plus a activation is the friction priced against all that compounding: slow to land and slow to repeat, so the engine wants a board where counters are already doing the heavy lifting and it only has to lean.