Watchful Radstag

Evolve normally caps out quietly: each larger creature adds a counter, the numbers creep up, and the card stays a single body growing sideways. This one weaponizes the trigger itself. Because it makes a full copy every time it evolves, the counter is no longer the reward; it's the fuse. The copies enter as base 2/2s (copy effects reproduce only printed characteristics, so the +1/+1 counter does not ride along), which is exactly what makes the loop dangerous rather than fair-looking. Every one of those 2/2 tokens carries evolve too, so a single body larger than a 2/2 will evolve all of the fresh tokens at once, and each of those evolves spawns another copy. The multiplication is broad rather than tall, and it feeds on precisely what green wants to be doing anyway: playing a curve of steadily larger bodies. The design tension lives in the "greater power or toughness" clause, which keeps the chain from being free. Note the shape of that clause carefully: once a token evolves it becomes a 3/3, so a subsequent 3/3 no longer clears its threshold and won't restart the older bodies; the ones that already grew are done, and only the newest crop of 2/2s reacts to the next arrival. The real limiter is your ability to keep dropping something larger than the freshest tokens each turn. It's a rare case of evolve, usually a passive value keyword, reframed as a token engine that snowballs off an escalating board.