Lilura, the Ninth Widow

At the beginning of your end step, sacrifice
another creature. Lilura, the Ninth Widow deals
X damage to each opponent, where X is equal to
the sacrificed creatures mana value. If you can't,
you lose 3 life, discard a card, then draw a card.
{3}{r}{r}: Transform Lilura. Activate only as a
sorcery, and only if you have 4 or more creatures
in your graveyard.