Mirror-Mad Phantasm + Sakashima's Will

Mirror-Mad Phantasm

Sakashima's Will

How it works

1. Cast Sakashima's Will by paying 3, causing you to gain control of a creature an opponent controls, then causing all creatures you control to become a copy of Mirror-Mad Phantasm until end of turn.
2. Activate the creature your opponent owns by paying 1, causing its owner to shuffle the creature into their library, and then mill their entire library.