Technomancer + Ashnod's Altar + Auton Soldier

Technomancer

Ashnod's Altar

Auton Soldier

How it works

1. Cast Technomancer by paying 5.
2. When Technomancer enters, it triggers, causing you to mill three cards and return Auton Soldier from your graveyard to the battlefield as a copy of Technomancer.
3. When Auton Soldier enters, it triggers. Holding priority, activate Ashnod's Altar by sacrificing Auton Soldier.
4. Resolve the Auton Soldier trigger, causing you to mill three cards and return Auton Soldier from your graveyard to the battlefield as a copy of Technomancer.
5. Repeat from step 3.

This loop relies on a clever recursive feedback between Technomancer and Auton Soldier, where entering the battlefield allows you to constantly pull your copycat right back out of the graveyard. By copying Technomancer, Auton Soldier triggers its own entry ability to loop the process, while Ashnod's Altar acts as the sacrificial engine that provides a steady stream of colorless mana and clears the way for the next iteration. Because Auton Soldier retains its artifact type thanks to its copy effect, this engine completely self-sustains to generate an endless cascade of sacrifices and triggered abilities.