
Enchantment
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.

Pays life for card advantage and explosive plays in black.

Black instant that draws cards by paying life.

Classic life-for-cards black draw.

Repeatable card advantage at the cost of life.

Black enchantment converting life and mana into cards.

Steady card advantage by paying life each turn.

Pay life to draw cards repeatedly in black.

Repeatable life-payment card draw enchantment.
→ Infinite card draw, Infinite draw triggers, Near-infinite lifegain
→ Each opponent loses the game, Near-infinite lifeloss for all players, Near-infinite self-discard triggers
→ Near-infinite lifegain, Near-infinite lifeloss
→ Win the game at the beginning of your next upkeep
→ Near-infinite lifeloss, Near-infinite card draw
→ Near-infinite lifeloss
You can't look at the cards exiled by the last ability while they're face down.
If a discarded card isn't put into your graveyard (due to an effect such as that of Obstinate Baloth) or leaves your graveyard (perhaps because another effect returned it to your hand), it won't be exiled.
If you discard a card with madness and wish to cast it, Necropotence's ability won't exile that card. If you don't wish to cast it, you choose whether it ends up exiled or in your graveyard.
Necropotence's last ability creates a delayed triggered ability that will put the exiled card into your hand. That ability still triggers even if Necropotence is removed from the battlefield before your end step.