Technomancer + Bartolomé del Presidio + Auton Soldier

Technomancer

Bartolomé del Presidio

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 Bartolomé del Presidio 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 hinges on a clever recursive resurrection engine fueled by Technomancer's entrance ability, which pulls Auton Soldier straight back from the graveyard. Because Auton Soldier enters as a non-legendary copy of Technomancer, its own ETB trigger goes on the stack to repeat the process, but you need Bartolomé del Presidio's sacrifice outlet to bin the copying clone before its trigger resolves so the chain can begin anew. By looping this sequence infinitely, you churn through your library with self-mill while stacking endless artifact and creature sacrifices, death triggers, and astronomical +1/+1 counters onto your sacrificial outlet.