Acererak, Archlich

When this creature transforms into Acererak,
Archlich, exile all cards from opponent's
graveyards.
If a card would go to an opponent's graveyard
from anywhere, exile it instead.
Opponents may not sacrifice dungeons.
If Acererak, Archlich would die, instead you
may pay 5 life. If you do, transform it and tap it.
It doesn't untap during your next untap step.