Cornerstone Portal

When you planeswalk to Cornerstone Portal or
at the beginning of your upkeep, exile target
creature you control. Return that creature to the
battlefield under your control at the beginning
of your next end step.
Whenever chaos ensues, exile cards from the top
of your library until you exile an artifact or
creature card. Put that card on the battlefield
tapped, and put the other exiled cards on the
bottom of your library in a random order.