Arte Fact, Curio Racketeer

Deathtouch
When Arte Fact enters the battlefield, look at the
top four cards of target opponent's library, exile
one of them face down, then put the rest on the
bottom of that library in a random order. You
may cast that card for as long as it remains exiled,
and mana of any type can be spent to cast it.
"Pretty decent gem you've got there."