Ancient Cellarspawn (Extended Art) [Duskmourn: House of Horror Commander]

Details

Each spell you cast that’s a Demon, Horror, or Nightmare costs {1} less to cast.
Whenever you cast a spell, if the amount of mana spent to cast it was less than its mana value, target opponent loses life equal to the difference. Where it treads, plants wither. Where it breathes, poison spreads.