Phantom Steed, Capture of Jingzhou, and The Immortal Weapons

Prerequisites

• Phantom Steed on the battlefield
• Capture of Jingzhou in hand
• The Immortal Weapons in exile
• each turn available

Steps

1. Cast Capture of Jingzhou by paying its mana cost, causing you to take an extra turn after this one Declare Phantom Steed as an attacker
2. It triggers, creating a token copy of The Immortal Weapons that's tapped and attacking
3. When the The Immortal Weapons token enters, it triggers, returning Capture of Jingzhou from your graveyard to your hand
4. Repeat each turn

Results

• Infinite turns
• Lock