Toph, the First Metalbender + Ugin's Nexus + Meticulous Excavation + Altar of Dementia

Toph, the First Metalbender

Ugin's Nexus

Meticulous Excavation

Altar of Dementia

How it works

1. Cast Ugin's Nexus by paying 5.
2. At the beginning of your end step, Toph triggers, causing Ugin's Nexus to become an artifact land creature.
3. Activate Altar of Dementia by sacrificing Ugin's Nexus. Ugin's Nexus is exiled instead of being put into your graveyard, causing you to take an extra turn after this one.
4. Toph triggers, returning Ugin's Nexus from exile to the battlefield.
5. Resolve the Altar of Dementia ability.
6. Activate Meticulous Excavation by paying 2, returning Ugin's Nexus from the battlefield to your hand.
7. Repeat each turn.

By redefining every nontoken artifact you control as a land, Toph, the First Metalbender turns Ugin's Nexus into a land artifact creature during your end step. This clever type shift lets you feed Ugin's Nexus directly to Altar of Dementia; because the Nexus's replacement effect exiles it to grant you an extra turn instead of letting it hit the graveyard, Toph's earthbend clause immediately rescues it right back to the battlefield. Finally, Meticulous Excavation ensures you can loop the Nexus back to your hand if needed, establishing a seamless and unbreakable chain of extra turns.