Mutie, Grave Witch

{1}{b}, {t}: Surveil 2. (Look at the top two cards of
your library, then put any number of them into your
graveyard and the rest on top of your library in any
order.)
Whenever one or more creature cards enter your
graveyard for the first time each turn, you may
exile one of them from your graveyard. If you do,
you may cast it this turn.