Unholy Annex // Ritual Chamber (Duskmourn: House of Horror Promos 118p) - Planeswalker Stamped - Rare Magic: The Gathering Card

At the beginning of your end step, draw a card. If you control a Demon, each opponent loses 2 life and you gain 2 life. Otherwise, you lose 2 life.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)