Altaïr Ibn-La'Ahad, Medomai the Ageless, and Ashes of the Fallen

Prerequisites

• Altaïr Ibn-La'Ahad on the battlefield
• Medomai the Ageless in the graveyard
• Ashes of the Fallen on the battlefield
• "Assassin" chosen with Ashes of the Fallen
• An opponent cannot block creatures you control

Steps

1. Declare Altaïr Ibn-La'Ahad as an attacker
2. Altaïr Ibn-La'Ahad triggers, exiling Medomai the Ageless from your graveyard with a memory counter on it as it is an Assassin due to Ashes of the Fallen, and then creating a tapped and attacking token copy of each creature you own in exile with a memory counter on it
3. Deal combat damage to an opponent using the Medomai the Ageless token
4. The Medomai the Ageless token triggers, causing you to take an extra turn after this one
5. At the end of your combat phase, Altaïr Ibn-La'Ahad triggers, exiling the Medomai the Ageless token
6. During the combat phase of your extra turn, declare Altaïr Ibn-La'Ahad as an attacker
7. Altaïr Ibn-La'Ahad triggers, creating a tapped and attacking token copy of each creature you own in exile with a memory counter on it
8. Repeat from step 3

Results

• Infinite extra turns