Mirror-Mad Phantasm and Cephalid Facetaker on the battlefield.
({1} magic symbol) ({U} magic symbol) available.
Steps
At the beginning of your combat phase, Cephalid Facetaker triggers, causing it to become a copy of Mirror-Mad Phantasm until end of turn.
Activate Cephalid Facetaker by paying ({1} magic symbol) ({U} magic symbol) , shuffling Cephalid Facetaker into your library and milling your entire library due to it not having a card named Mirror-Mad Phantasm in it.