Progenitor Mimic, Time Walk, and Mnemonic Wall

Prerequisites

• Progenitor Mimic on the battlefield
• Time Walk on the battlefield
• Mnemonic Wall on the battlefield
• Enough mana available to cast the extra turn spell each turn
• Progenitor Mimic is a copy of Mnemonic Wall

Steps

1. Cast Time Walk by paying its mana cost, taking an extra turn after this one
2. At the beginning of your next upkeep, Progenitor Mimic triggers, creating a token copy of Mnemonic Wall
3. When the token Mnemonic Wall enters the battlefield, it triggers itself, returning Time Walk from your graveyard to your hand
4. Repeat

Results

• Infinite turns