Activate Coretapper's second ability by sacrificing it, putting two charge counters on Magistrate's Scepter.
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.
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.
Activate Power Conduit by tapping it and removing the finality counter from Coretapper, putting a charge counter on Magistrate's Scepter.
Repeat from step 2 each turn.

Infinite turns

Lock

Mirko, Obsessive Theorist

Coretapper

Magistrate's Scepter

Power Conduit

Activate Coretapper's first ability by tapping it, putting a charge counter on Magistrate's Scepter.
Activate Coretapper's second ability by sacrificing it, putting two charge counters on Magistrate's Scepter.
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.
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.
Activate Hex Parasite by paying {1}{B/P}, removing the finality counter from Coretapper and giving Hex Parasite +1/+0 until end of turn.
Repeat each turn.

Combos with "Mirko, Obsessive Theorist"