Emry, Lurker of the Loch + Ugin's Nexus + Isochron Scepter + Pull from Eternity + Lithatog

Emry, Lurker of the Loch

Ugin's Nexus

Isochron Scepter

Pull from Eternity

Lithatog

How it works

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 2 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. Activate Emry by tapping it, targeting Ugin's Nexus.
7. Cast Ugin's Nexus from your graveyard by paying 5.
8. Repeat.

This intricate loop bends time to your will by continuously recycling Ugin's Nexus to take endless extra turns. You begin by sacrificing the Nexus to Lithatog, whose ability triggers the artifact's replacement effect to exile itself and grant you an extra turn. Once you reach that bonus turn, Isochron Scepter goes to work, tapping to cast a copied Pull from Eternity that rescues the Nexus straight out of exile and drops it into your graveyard. From there, Emry, Lurker of the Loch steps in to let you recast the Nexus from the graveyard, setting the whole sequence up to repeat indefinitely.