Medomai the Ageless, and The Neutrinos

Prerequisites

• Medomai the Ageless on the battlefield
• The Neutrinos on the battlefield

Steps

1. Declare The Neutrinos as an attacker, triggering its second ability, blinking Medomai and causing it to enter tapped and attacking
2. Deal combat damage using Medomai, triggering its ability, causing you to take an extra turn after this one
3. Repeat each turn

Results

• Infinite turns
• Lock