Grathorn, Beast Master

{x} exile cards from the top of your library until
you exile a creature with a converted mana cost
X or less. You may play that creature card this
turn without paying its mana cost. Put all cards
exiled this way that you did not play on the
bottom of your library in a random order
{t} sacrifice target creature with power and
toughness X/Y gain Y life, and give Grathorn
Beast Master +X/+0 until end of turn.