Elus, Keeper of Lost Memories

When Elus enters the battlefield, scry 2.
{t}: Exile the bottom card of your library
face down.
When Elus leaves the battlefield, you may reveal
all cards exiled with it. For each noncreature,
nonland card revealed this way, you may cast it
without paying its mana cost. Shuffle all the cards
you didn't cast this way into your library.