The Sixth Doctor, Ugin's Nexus, Meticulous Excavation, and Krark-Clan Ironworks

Prerequisites

• The Sixth Doctor on the battlefield
• Ugin's Nexus in hand
• Meticulous Excavation on the battlefield
• Krark-Clan Ironworks on the battlefield
• each turn available

Steps

1. Cast Ugin's Nexus by paying
2. The Sixth Doctor triggers, copying the Ugin's Nexus spell, with the copy being nonlegendary
3. Resolve both Ugin's Nexus spells
4. Activate Krark-Clan Ironworks by sacrificing the Ugin's Nexus token, adding
5. The Ugin's Nexus token is exiled instead of being put into your graveyard, causing you to take an extra turn after this one
6. Activate Meticulous Excavation by paying , returning the nontoken Ugin's Nexus to your hand
7. Repeat each turn

Results

• Infinite turns