True Katos

Flying, Deathtouch, Ward{3}
As True Katos enters the battlefield, you
may pay {p/r}{p/b}. If you don't, it enters the battlefield tapped.
Whenever True Katos attacks, you may mill
X cards, where X is the number of cards in
your hand. If you do, True Katos gets +X+X until end of turn.