Grim Lavamancer

Flying Whenever this creature deals damage, you gain that much life. Morph 2WW (You may cast this card face down as a 2/2 creature for 3. Turn it face up any time for its morph cost.)

X, Sacrifice this enchantment: Destroy each artifact, creature, and enchantment with mana value X or less.

As this creature enters, choose a nonland card name. Spells with the chosen name can't be cast.