The Unknown Wizard (UNK-MZ01) - Unknown Event

Eminence — As long as The Unknown Wizard is in the command zone or on the battlefield, other playtest cards you cast cost {1} less to cast.
Whenever The Unknown Wizard enters or attacks, look at the top ten cards of your library. You may put a legendary playtest card from among them onto the battlefield. Put the rest on the bottom in a random order.