Curse of the Abyss

At the beginning of each opponent's upkeep, that player loses 1 life for each card in their hand more than 4. Whenever an opponent loses life, you may gain that much life.
{3}{b}{b}, Sacrifice Curse of the Abyss: Each opponent discards cards until they
have four cards in their hand, then draw
cards equal to the life you gained this turn."