Phantom Steed, Time Walk, and Mnemonic Wall

Prerequisites

• Phantom Steed on the battlefield
• Time Walk in hand
• Mnemonic Wall in exile
• An opponent can not block Phantom Steed
• available

Steps

1. Cast Time Walk, taking an extra turn after this one
2. Attack with Phantom Steed
3. Phantom Steed triggers, creating a token copy of Mnemonic Wall that is tapped and attacking
4. Mnemonic Wall enters, returning Time Walk from your graveyard to your hand
5. Pass the turn
6. Repeat

Results

• Infinite turns