Mirror-Mad Phantasm, and Unstable Shapeshifter

Prerequisites

• Mirror-Mad Phantasm in hand
• Unstable Shapeshifter on the battlefield
• available

Steps

1. Cast Mirror-Mad Phantasm by paying
2. When Mirror-Mad Phantasm enters the battlefield, Unstable Shapeshifter triggers, causing Unstable Shapeshifter to become a copy of Mirror-Mad Phantasm until end of turn
3. Activate Unstable Shapeshifter by paying , shuffling Unstable Shapeshifter into your library and milling your entire library due to it not having a card named Mirror-Mad Phantasm in it

Results

• Infinite self-mill