Necropotence is a mythic Enchantment card from Secret Lair Countdown (SLC), collector number 1995. Current market price: $45.67 (foil $85.46), TCGplayer market prices via Scryfall.
Skip your draw step. Whenever you discard a card, exile that card from your graveyard. Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.