Ugin's Nexus + Esoteric Duplicator + Extruder

Ugin's Nexus

Esoteric Duplicator

Extruder

How it works

1. During your end step, activate Extruder 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 Extruder ability, putting a +1/+1 counter on a creature you control.
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 engine lets you chain together infinite turns by weaponizing the replacement effects of Ugin's Nexus. When you feed the Nexus to Extruder's sacrifice ability during your end step, the Nexus replaces its own trip to the graveyard by exiling itself, which immediately grants you an extra turn while slipping past its own clause preventing extra turns. Meanwhile, Esoteric Duplicator watches your sacrifice and lets you pay {2} to effortlessly reproduce the Nexus at the next end step, ensuring you have a fresh copy ready to lock down the game and repeat the cycle indefinitely.