Chittering Harvester

Mutate as a mechanic mostly built value engines: you paid the mutate cost to stack abilities and reset the pile's power and toughness, and the payoff was usually card advantage or a triggered bonus. This one weaponizes the act of mutating itself. Because a mutate trigger fires every time you add to the pile, an edict rider on that trigger turns a normally durdly, incremental process into repeatable, cumulative removal: the more creatures you glue together, the more your opponents shed. That reframes the mechanic from a bench of stat upgrades into a slow grind of forced sacrifices, and it sidesteps the usual weakness of edict effects (a board full of expendable chaff to feed the requirement) by punishing every mutate you can afford rather than a single one-shot cast. The 4/6 body underneath is a deliberately durable base to build on, cheap to trade into on defense and stubborn enough to survive the attrition you are forcing. It is a Nightmare, not a beast to ramp into, and the design leans into that: it does not care about being the top of the pile so much as being present when the pile grows. Where most mutate cards ask what you gain by stacking, this one asks what your opponent loses, and it keeps asking as long as you keep building.