Shavath, of Dreams and Death

When Shavath enters the battlefield, each player discards their hand, then loses 2 life for each card discarded this way.
Nightmares you control get +1/+1 for each card in your graveyard.
If you would draw a card while your library has no cards in it, you do not lose the game. Instead choose 10 cards in your graveyard an put them on top of your library in a random order.
Nightmares you control can attack, and only attack during your opponents combat phase.