Kaya the Inexorable + Ugin's Nexus + Karn, the Great Creator + Viscera Seer

Kaya the Inexorable

Ugin's Nexus

Karn, the Great Creator

Viscera Seer

How it works

1. Activate Karn's first loyalty ability by putting a loyalty counter on it, causing Ugin's Nexus to become an artifact creature until end of turn.
2. Activate Kaya's first loyalty ability by putting a loyalty counter on it, putting a ghostform counter on Ugin's Nexus.
3. Activate Viscera Seer by sacrificing Ugin's Nexus.
4. Ugin's Nexus is exiled instead of being put into your graveyard, causing you to take an extra turn after this one.
5. Ugin's Nexus triggers, returning itself from exile to your hand, and creating a 1/1 Spirit creature token.
6. Resolve the Viscera Seer ability from step 3, causing you to scry 1.
7. Move to your next turn.
8. Cast Ugin's Nexus by paying 5.
9. Repeat.