Extractor Demon

The mill happens on a trigger most creature-heavy decks generate without trying: every death, sacrifice, bounce, or exile on either side of the table feeds two cards into a graveyard. That breadth is the design hook. A board wipe doesn't just clear the field, it dumps a dozen cards into someone's bin; an aristocrats engine grinding its own bodies turns into a passive mill machine running in the background. The wording is "another creature leaves the battlefield," wider than a plain death trigger: it catches blinks, returns to hand, and exile effects too. The exception is telling. This demon's own unearth exile does not feed it, because "another" excludes itself, so the engine only runs while something else is leaving. The recursion is the body's second act, but a strictly single-use one. A 5/5 flier at six mana is a slow first cast; for it can claw back from the graveyard with haste for one swing before it removes itself from the game for good. So unearth buys you exactly one extra attack and one extra window of leaves-the-battlefield triggers, not an ongoing loop. What the card really asks is that you read leaves-the-battlefield events as a resource rather than incidental noise, and the value of the two-card mill, finisher or nuisance, depends entirely on how much your shell is willing to keep dying.