Emry, Lurker of the Loch + Ugin's Nexus + Isochron Scepter + Pull from Eternity + Krark-Clan Grunt

Emry, Lurker of the Loch

Ugin's Nexus

Isochron Scepter

Pull from Eternity

Krark-Clan Grunt

How it works

1. Activate Krark-Clan Grunt by sacrificing Ugin's Nexus.
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.