Owlbear Cub, Medomai the Ageless, Hua Tuo, Honored Physician, and Ashnod's Altar

Prerequisites

• Owlbear Cub on the battlefield
• Medomai the Ageless in the graveyard
• Hua Tuo, Honored Physician on the battlefield
• Ashnod's Altar on the battlefield
• Owlbear Cub and Hua Tuo do not have summoning sickness
• An opponent controls at least eight lands and is unable to block and kill your creatures

Steps

1. Activate Hua Tuo by tapping it, putting Medomai on top of your library from your graveyard
2. Move to your combat phase, and declare Owlbear Cub as an attacker, attacking the opponent with eight or more lands
3. Owlbear Cub triggers, causing you to look at the top eight cards of your library, put Medomai onto the battlefield tapped and attacking, and put the remaining cards on the bottom of your library
4. Deal combat damage with Owlbear Cub and Medomai
5. Medomai triggers, causing you to take an extra turn after this one
6. Activate Ashnod's Altar by sacrificing Medomai, adding
7. Repeat each turn

Results

• Infinite turns