Osgir, the Reconstructor + Karn, the Great Creator + Ugin's Nexus + Parallel Lives + Putrid Imp

Osgir, the Reconstructor

Karn, the Great Creator

Ugin's Nexus

Parallel Lives

Putrid Imp

How it works

1. Activate Osgir by paying 5, tapping it and exiling Ugin's Nexus from your graveyard, creating four token copies of Ugin's Nexus.
2. Put three of the Ugin's Nexus tokens into exile due to the legend rule and their replacement effects, causing you to take three extra turns after this one.
3. Activate Karn's first loyalty ability by putting a loyalty counter on it, choosing to do nothing.
4. Move to your next extra turn.
5. Repeat from step 3 one additional time.
6. Activate Karn's second loyalty ability by removing two loyalty counters from it, returning Ugin's Nexus from exile to your hand.
7. Activate Putrid Imp by discarding Ugin's Nexus.
8. Move to your last extra turn.
9. Repeat.