Unakyr, Graveyard Devourer

Flying, Deathtouch
When this creature enters the battlefield, exile all cards in all graveyards.
{p/b}{p/g}: Shuffle your graveyard into your library.
{b}{b}: Regenerate Unakyr.
{t}: Put the bottom two cards of your library into your grave yard and gain two life.
Enter graveyards have been swallowed by this behemoth.