Slifer, The Sky Dragon

This spell cannot be countered.
As an additional cost to cast this spell, sacrifice three non-token creatures.

Flying, indestructible, haste

Slifer, The Sky Dragon's power and toughness are equal to the number of cards in your hand.

Creatures your opponents control enter the battlefield with three -1/-1 counters on them, then if it's power is reduced to zero this way, destroy that creature.