Slifer the Sky Dragon

Shroud, Flying, Split Second
As an additional casting cost, sacrifice three non
-token creatures. If Slifer would be exiled,
shuffle it into its owner's deck instead. If this
creature entered the battlefield and was not cast,
sacrifice it at the beginning of the next end step.
Slifer's power and toughness are equal to twice
the number of cards in your hand. Creatures your
opponents control have -4/-4.