Slifer the Sky Dragon

This spell can't be countered.
Indestructible, Trample, Vigilance, Haste
Slifer the Sky Dragon gains +X/+X where X is the number of cards in your hand.
When Slifer enters the battlefield, draw cards until you have 7 cards in your hand.
If Slifer enters the battlefield, but wasn't cast, sacrifice him during the next End Step.
If a creature enters the battlefield under an opponent's control, it gains 5 -1/-1 counters.