Planar Anarchy

Planar Anarchy enters the battlefield tapped.
{t}: Add {r} to your mana pool.
{r}{r}{r}, {t}, Sacrifice a creature you control:
Reveal cards from the top of your library until
you reveal a creature card. Put the revealed card
onto the battlefield under your control and the
rest of the revealed cards onto the bottom of
your library in a random order.