Khamûl, Dol Guldur Successor

{1}, Pay 3 life, or {1}, Sacrifice a creature, or {1}{b}{b}, or {1}, Discard a card: Choose one.
Pay each of these costs only once each turn —
• Target player draws a card and loses 1 life.
• Add {b}{b}.
• Target player sacrifices a creature.
{bull} You gain 3 life.