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

Karn, the Great Creator

Displacer Kitten

Ugin's Nexus

Arcbound Ravager

How it works

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 5.
7. Displacer Kitten triggers, blinking Karn.
8. Repeat.