Eternal Taskmaster, Coretapper, and Magistrate's Scepter

Prerequisites

• Eternal Taskmaster on the battlefield
• Coretapper on the battlefield
• Magistrate's Scepter on the battlefield
• Coretapper and Eternal Taskmaster do not have summoning sickness
• An opponent cannot block and kill Eternal Taskmaster
• each turn available

Steps

1. Activate Coretapper's first ability by tapping it, putting a charge counter on Magistrate's Scepter
2. Activate Coretapper's second ability by sacrificing it, putting two charge counters on Magistrate's Scepter
3. Activate Magistrate's Scepter's second ability by tapping it and removing three charge counters from it, taking an extra turn after this one
4. Declare Eternal Taskmaster as an attacker
5. Eternal Taskmaster triggers, causing you to pay to return Coretapper from your graveyard to your hand
6. In your postcombat main phase, cast Coretapper by paying
7. Repeat each turn

Results

• Infinite turns