Silas Renn, Seeker Adept + Ugin's Nexus + Isochron Scepter + Pull from Eternity + Krark-Clan Ironworks

Silas Renn, Seeker Adept

Ugin's Nexus

Isochron Scepter

Pull from Eternity

Krark-Clan Ironworks

How it works

1. Activate Krark-Clan Ironworks by sacrificing Ugin's Nexus, adding CC.
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. Deal combat damage to an opponent using Silas Renn, triggering Silas Renn, targeting Ugin's Nexus.
7. Cast Ugin's Nexus from your graveyard by paying 5.
8. Repeat.

This intricate engine manages to take infinite turns by repeatedly cycling Ugin's Nexus through your graveyard and exile. While Krark-Clan Ironworks provides the initial mana and sacrificial trigger to send Ugin's Nexus into exile for its extra turn, Isochron Scepter—imprinted with Pull from Eternity—rescues it back into the graveyard so Silas Renn, Seeker Adept can recast it following combat damage.