Activate Isochron Scepter by paying {2} and tapping it, casting a copy of Moonmist without paying its mana cost.
Resolve Moonmist, transforming Ultimecia, Time Sorceress into Ultimecia, Omnipotent.
Ultimecia, Omnipotent triggers, causing you to take an extra turn after this one.
At the beginning of your end step, Conjurer's Closet triggers, blinking Ultimecia, Omnipotent and causing it to re-enter the battlefield as Ultimecia, Time Sorceress.
Whenever Ultimecia, Time Sorceress enters the battlefield, it triggers, causing you to surveil 2.
Repeat each turn.

Infinite turns

Lock

Ultimecia, Time Sorceress // Ultimecia, Omnipotent

Moonmist

Isochron Scepter

Conjurer's Closet

At the beginning of your upkeep, Panoptic Mirror triggers, casting a copy of Moonmist without paying its mana cost.
Resolve Moonmist, transforming Ultimecia, Time Sorceress into Ultimecia, Omnipotent.
Ultimecia, Omnipotent triggers, causing you to take an extra turn after this one.
At the beginning of your end step, Airbender Ascension triggers, blinking Ultimecia, Omnipotent and causing it to re-enter the battlefield as Ultimecia, Time Sorceress.
Whenever Ultimecia, Time Sorceress enters the battlefield, it triggers, causing you to surveil 2.
Repeat each turn.

Combos with "Moonmist"