Spiritmonger

Trading into a 6/6 for five is already a losing proposition; this one punishes the block specifically, walking away with a +1/+1 counter every time it connects with a creature. That combat trigger is the engine, but the two activated abilities are what turned a big body into a removal-magnet that refused to stay dead. Regeneration on a single black mana keeps it out of reach of most effects that destroy rather than exile, and the color-shifting line is the quiet card-saver: one green mana turns it white to dodge a black-only removal spell, or off-color to slip past a protection-from clause. Together those three lines make a creature that grinds, regrows, and reshapes itself faster than an opponent can find the one answer that sticks. It arrived at a moment when a six-power green-black creature with this much built-in resilience was genuinely hard to kill in combat or with targeted removal, and it spent years as the kind of midrange threat that closed games by attrition rather than tempo. The design lineage it sits in (the fattie that demands a specific answer, not just any answer) runs through black-green's whole history, and this was one of the early, clean statements of it: a Golgari flagship beater before "Golgari" was a word players reached for.