Uhthulc, the All-Consuming

When Uhthulc, the All-Consuming enter the battlefield, exile all graveyards. If a card would be
put into a graveyard, exile it instead. At the
beginning of each players upkeep, they must sacrifice a creature. If they don't, Uhthulc, the
All-Consuming deals five damage to that player.
Uhthulc, the All-Consuming's power and
toughness is equal to the number of cards in
exile.