Karn, the Great Creator, Displacer Kitten, Ugin's Nexus, and Arcbound Ravager

Prerequisites

• Karn, the Great Creator on the battlefield
• Displacer Kitten on the battlefield
• Ugin's Nexus on the battlefield
• Arcbound Ravager on the battlefield
• Karn has at least three loyalty counters
• on each extra turn available

Steps

1. Activate Arcbound Ravager by sacrificing Ugin's Nexus
2. Ugin's Nexus is exiled instead of being put into your graveyard, causing you to take an extra turn after this one
3. Resolve the Arcbound Ravager ability, putting a +1/+1 counter on it
4. Activate Karn's second ability by removing two loyalty counters from it, putting Ugin's Nexus into your hand from exile
5. Move to your next turn
6. Cast Ugin's Nexus by paying
7. Displacer Kitten triggers, blinking Karn
8. Repeat

Results

• Infinite turns