Ugin's Nexus + Esoteric Duplicator + Lithatog

Ugin's Nexus

Esoteric Duplicator

Lithatog

How it works

1. During your end step, activate Lithatog's first ability 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. Esoteric Duplicator triggers, causing you to pay 2 to create a token copy of Ugin's Nexus at the beginning of your next end step.
4. Resolve the Lithatog ability, giving it +1/+1 until end of turn.
5. Move to your extra turn.
6. At the beginning of your end step, Esoteric Duplicator triggers, creating a token copy of Ugin's Nexus.
7. Repeat.

This clever loop hinges on the replacement effects of Ugin's Nexus, which turns its own destruction into an extra turn rather than heading to the graveyard. By feeding the Nexus to Lithatog during your end step, you cleanly trigger the artifact's graveyard replacement while giving your creature a power boost. Meanwhile, Esoteric Duplicator watches your artifacts head to the bin and lets you pay `{2}` to smoothly reproduce Ugin's Nexus at the next end step, locking down infinite turns.