Mirko, Obsessive Theorist + Coretapper + Magistrate's Scepter + Power Conduit

Mirko, Obsessive Theorist

Coretapper

Magistrate's Scepter

Power Conduit

How it works

1. Activate Coretapper's second ability by sacrificing it, putting two charge counters on Magistrate's Scepter.
2. Activate Magistrate's Scepter's second ability by tapping it and removing three charge counters from it, causing you to take an extra turn after this one.
3. At the beginning of your end step, Mirko's last ability triggers, returning Coretapper from your graveyard to the battlefield with a finality counter on it.
4. Activate Power Conduit by tapping it and removing the finality counter from Coretapper, putting a charge counter on Magistrate's Scepter.
5. Repeat from step 2 each turn.

This clever loop chains together artifact manipulation and graveyard recursion to steal infinite turns right out from under your opponents. By sacrificing Coretapper, you instantly seed Magistrate's Scepter with the charge counters it needs to grant you an extra turn. Meanwhile, Mirko, Obsessive Theorist watches from the command zone or battlefield, ready to bring Coretapper right back from the graveyard at your end step despite its pesky finality counter. Finally, Power Conduit steps in to cleanly strip that finality counter away—repurposing it into yet another charge counter for Magistrate's Scepter to keep the endless loop humming turn after turn.