Smokemage

Flash
When Smokemage enters the battlefield under
your control, exile it and X other creatures you
own in a face-down pile, shuffle that pile, then
manifest all cards in that pile. (To manifest a
card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost
if it's a creature card.)
"Now you see us, now you don't."