Muldrotha, the Gravetide, Ugin's Nexus, Isochron Scepter, Pull from Eternity, and Lithatog

Prerequisites

• Muldrotha, the Gravetide on the battlefield
• Ugin's Nexus on the battlefield
• Isochron Scepter on the battlefield
• Pull from Eternity in exile
• Lithatog on the battlefield
• each extra turn available

Steps

1. Activate Lithatog's first ability by sacrificing Ugin's Nexus, giving it +1/+1 until end of turn
2. When Ugin's Nexus is sacrificed, it is exiled instead of being put into your graveyard, causing you to take an extra turn after this one
3. Move to your next turn
4. Activate Isochron Scepter by paying and tapping it, casting a copy of Pull from Eternity without paying its mana cost
5. Resolve Pull from Eternity, putting Ugin's Nexus from exile into your graveyard
6. Cast Ugin's Nexus from your graveyard by paying
7. Repeat

Results

• Infinite turns