Medomai the Ageless + Idris, Soul of the TARDIS + Karn's Bastion + Thran Forge

Medomai the Ageless

Idris, Soul of the TARDIS

Karn's Bastion

Thran Forge

How it works

1. Activate Thran Forge by paying 2, causing Medomai the Ageless to become an artifact until end of turn and get +1/+0 until end of turn.
2. Deal combat damage to an opponent using Medomai the Ageless.
3. Medomai the Ageless triggers, causing you to take an extra turn after this one.
4. Cast Idris by paying 1.
5. When Idris enters the battlefield, it triggers, exiling Medomai the Ageless until Idris leaves the battlefield.
6. Move to your extra turn.
7. At the beginning of your upkeep, Idris's vanishing ability triggers, removing a time counter from it.
8. Activate Karn's Bastion's second ability by paying 4 and tapping it, putting a time counter on Idris.
9. Deal combat damage to an opponent using Idris.
10. Idris triggers, causing you to take an extra turn after this one.
11. Repeat from step 6.