Mystical Extraction

Search target opponent's library for a card and
exile it face down. Then that player shuffles their library. You may look 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. You skip your next turn.
"A rather risky technique for the unprepared, but my
choice is almost next to nothing."
—Rafael, fallen angel