Slifer the Sky Dragon

Reveal this card from your hand and sacrifice
three creatures: Put this card onto the battlefield
under your control. Activate this ability only as
a sorcery.
Slifer the Sky Dragon can't be countered.
Flying, haste, vigilance
If a creature an opponent controls has 0 or fewer
power, destroy it. They get -4/-0.
This card's power and toughness are each equal
to twice the number of cards in your hand.