Thief of Sanity

Flying
Whenever Thief of Sanity deals combat damage
to a player, look at the top three cards of that
player's library, exile one of them face down,
then put the rest into their graveyard. You may
look at and cast that card for as long as it remains
exiled, and you may spend mana as though it
were mana of any type to cast that spell.
There's a fine line between the Method actor and the schizophrenic. - Nicolas Cage