Gelatinous Cube

Removal that eats and refuses to give the meal back. Most exile-on-enter creatures play a straightforward game: the threat comes off the board while the vessel lives, and killing the vessel reverses the deal. This one runs a second clock. Engulf handles the temporary part, holding a non-Ooze creature in stasis, but Dissolve converts that hostage into a permanent kill: pay , with X equal to the exiled card's mana value, and the creature goes to the graveyard rather than home. That turns the usual "kill the Cube, get your creature back" counterplay into a race, because a live Cube on your opponent's turn threatens to digest whatever it is holding. The scaling cost is the balancing wrinkle: dissolving a one-drop asks for almost nothing, while a game-ending fatty demands real mana, so the card is a cheap answer to small threats and an expensive commitment against big ones. The Ooze exception cuts both ways: the Cube cannot engulf its own kind, and against an Ooze-heavy board it is a 4/3 with nothing to eat. What separates it from a plain black take on Banisher Priest is that the exile is not merely conditional on the body surviving; it is a countdown, and the controller decides when the clock runs out.