Slifer the Sky dragon

You may also sacrifice 3 creatures to use. This
creature's power and toughness in equal to the
number of cards in your hand times 3. If you
control a creature with {4} or {9} mana cost:
All creatures you control have 20 toughness.
All your opponent's creatures lose 2 power and toughness.
The heavens twist and thunder roars, signalling
the coming of this ancient creature and the dawn
of true power.