Arthur, Marigold Knight, Medomai the Ageless, and Scroll Rack

Prerequisites

• Arthur, Marigold Knight on the battlefield
• Medomai the Ageless in hand
• Scroll Rack on the battlefield
• You control at least one other creature that does not have summoning sickness
• An opponent cannot block creatures you control
• each turn available

Steps

1. Activate Scroll Rack by paying and tapping it, causing you to exile Medomai the Ageless from your hand and put the top card of your library into your hand, then put Medomai the Ageless from exile on top of your library
2. Declare Arthur and at least one other creature as attackers
3. Arthur triggers, causing you to reveal the top six cards of your library and put Medomai the Ageless onto the battlefield tapped and attacking
4. Deal combat damage using Medomai the Ageless
5. Medomai the Ageless triggers, causing you to take an extra turn after this one
6. At the end of your combat phase, Arthur triggers, returning Medomai the Ageless from the battlefield to your hand
7. Repeat each turn

Results

• Infinite turns