Valgrun, Gifter of Lost Tales

When Valgrun enters, reveal cards from the top of your library until you reveal an enchantment card with mana value X. Exile it and put the rest on the bottom of your library in any order. For as long as that card remains exiled, you may cast it.

{3}{r}{g}{t}: Exile target enchantment you control. Return it to the battlefield under its owner's control at the beginning of the next end step.