Menelkir, Arcanum Archmage

When Menelkir, Arcanum Archmage enters the battlefield, search target opponent's library for a card and exile it face down. You may look a that card at any time, and you may cast it during your turn.
{u}{u}{b}: Put Menelkir on top of it's owners library and put each card exiled with it into
it's owners graveyard. Activate this ability only during your turn.