Goldryg, Dragon of the Dead

Flying, Trample, Deathtouch, Menace
When Goldryg, Dragon of the Dead enters the
battlefield, exile all cards from all graveyards.
Goldryg, Dragon of the Dead gets +X/+X,
where X is equal to half the number of cards
exiled this way (rounded up). At each of your
main phases, you may cast any of the cards exiled
this way.