Volrath's Shapeshifter

A clone that reads off the wrong zone, and the design discipline lives in that single word: graveyard, not battlefield. Every other shapeshifter of its era copies a creature in play; this one copies whatever creature card is sitting on top of your discard pile, which means the body you get is something you chose to throw away rather than something an opponent left exposed. That inversion is what the repeatable discard ability is for. The ": Discard a card" clause is not incidental upkeep cost; it is the steering wheel. Pitch a creature and the Shapeshifter becomes that creature until you pitch over it; pitch a noncreature card and it reverts to a 0/1 with nothing but the discard ability, ready to dig for the next body. The whole card is a manual graveyard-toolbox engine built years before "delve" or "flashback" made the graveyard a resource players expected to mine on purpose. It rewards a deck stocked with fat creatures you are happy to discard and happy to become, and it punishes a deck that just plays good cards, because every noncreature card on top is a wasted turn of identity. The fragility is real (a single milling effect or an opponent's graveyard hate rewrites who it is), but the conceptual reach is unusual: a permanent whose printed text is almost entirely a pointer to text written somewhere else.