Farbog Boneflinger
Five mana for a 2/2 looks like a bad rate until you stop reading the body as the product. The Zombie is incidental shipping; the cargo is the enters-the-battlefield -2/-2, a removal effect stapled to a creature so it can be blinked, reanimated, bounced, and replayed for the kill clause again. That reusability is exactly why the body stays small and the toughness stays fragile: a recurring source of -2/-2 is a different animal than a one-shot edict, and the price is paid in the slow, unthreatening shell wrapped around it. The -2/-2 also reaches a corner of the removal grid that damage misses. It kills the indestructible, shrinks an attacker out of a profitable block, and erases tokens and one-toughness utility creatures wholesale, all without targeting restrictions beyond "creature." Sized at -2/-2 rather than -X/-X, it is deliberately a small-creature answer, not a finisher remover, which is the line that keeps a repeatable effect from being oppressive. The lineage runs straight through every creature that turned a removal spell into a permanent you get to abuse on the way down: the Flinger asks the same question those cards do, which is not "is this a good creature" but "how many times can I make it enter."

