Karn, the Great Creator + Displacer Kitten + Ugin's Nexus + Krark-Clan Ironworks

Karn, the Great Creator

Displacer Kitten

Ugin's Nexus

Krark-Clan Ironworks

How it works

1. Activate Krark-Clan Ironworks by sacrificing Ugin's Nexus, adding CC.
2. Ugin's Nexus is exiled instead of being put into your graveyard, causing you to take an extra turn after this one.
3. Activate Karn's second ability by removing two loyalty counters from it, putting Ugin's Nexus into your hand from exile.
4. Move to your next turn.
5. Cast Ugin's Nexus by paying 5.
6. Displacer Kitten triggers, blinking Karn.
7. Repeat.