Gonti's Aether Heart, Mishra, Eminent One, and Urza, Prince of Kroog

Prerequisites

• Gonti's Aether Heart on the battlefield
• Mishra, Eminent One on the battlefield
• Urza, Prince of Kroog on the battlefield
• each turn available

Steps

1. At the beginning of combat, Mishra triggers, creating a 4/4 artifact creature token copy of Gonti's Aether Heart named Mishra's Warform
2. Mishra's Warform enters the battlefield, triggering itself and Gonti's Aether Heart, causing you to get four energy counters
3. Activate Urza by paying , creating a 3/3 Soldier artifact creature token copy of Gonti's Aether Heart
4. Put the token copy of Gonti's Aether Heart into the graveyard due to the legend rule
5. The Gonti's Aether Heart token entering the battlefield triggers Mishra's Warform and Gonti's Aether Heart and itself, causing you to get six energy counters
6. Activate Mishra's Warform by paying eight energy counters and exiling it, taking an extra turn after this one
7. Repeat each turn

Results

• Infinite turns