Slithering Shade

The Shade has always been black's cleanest mana-sink threat: spend mana, grow, swing for whatever your lands can support. This one inverts the deal. Out of the gate it is a wall that cannot attack, a 0/1 that pumps but goes nowhere with the buff. The hellbent clause is the switch: empty your hand and the defender stops mattering, turning a stalling body into the same scalable beater the classic Shade has always been. That makes it a referendum on a particular kind of black deck, the discard-heavy build that wants its grip empty anyway. While you hold cards it backs up the early turns and trades defensively; once you have dumped everything, it becomes a finisher whose ceiling is bounded only by your remaining mana. The friction is sequencing: there is no help getting to an empty hand, so the creature stays inert until your whole grip has been spent, which is precisely the schedule the deck it was built for already runs on. Hoarding lands and tricks in reserve is exactly what disarms it; emptying out fast is what arms it. A Shade that punishes holding cards is a tidy bit of design tension, since the resource that usually keeps a player safe is the one this creature needs spent down to nothing.