Miasma Demon is a uncommon Creature — Demon card from Duskmourn: House of Horror (DSK), collector number 109. Current market price: $0.19 (foil $0.27), TCGplayer market prices via Scryfall.
Flying When this creature enters, you may discard any number of cards. When you do, up to that many target creatures each get -2/-2 until end of turn.