Bleached Bones

When Bleached Bones enters the battlefield, destroy all creatures.
At the beginning of each player's upkeep, that player exiles a card from his or her graveyard and creates a 1/1 black Skeleton creature token.
Then, if there are no cards in that player's graveyard, put a bone counter on Bleached Bones.
Remove X bone counters from Bleached Bones: Draw X cards and you lose X life.