Slifer The Skydragon

As an additional cost to cast this spell, sacrifice 3 creatures.

Flying, Ward-discard two cards.

Each creature your opponents control enters with two -1/-1 counters on it.

Slifer The Skydragon's power and toughness
are each equal to the number of cards in your
hand. Sacrifice Slifer at the end of your turn if he wasn't cast.