Medomai the Ageless + Idris, Soul of the TARDIS + Thrummingbird + Encroaching Mycosynth

Prerequisites

• An opponent cannot block creatures you control.

Steps

1. 1Deal combat damage to an opponent using Medomai the Ageless.
2. 2Medomai the Ageless triggers, causing you to take an extra turn after this one.
3. 3Cast Idris by paying .
4. 4When Idris enters the battlefield, it triggers, exiling Medomai the Ageless until Idris leaves the battlefield.
5. 5Move to your extra turn.
6. 6At the beginning of your upkeep, Idris's vanishing ability triggers, removing a time counter from it.
7. 7Deal combat damage to an opponent using Idris and Thrummingbird.
8. 8Idris and Thrummingbird trigger.
9. 9Resolve the Idris trigger, causing you to take an extra turn after this one.
10. 10Resolve the Thrummingbird trigger, putting a time counter on Idris.
11. 11Repeat from step 5.

Effects

• Infinite turns
• Lock