Sigil of the New Dawn, Coretapper, and Magistrate's Scepter

Prerequisites

• Sigil of the New Dawn on the battlefield
• Coretapper on the battlefield
• Magistrate's Scepter on the battlefield
• Coretapper does not have summoning sickness
• 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
3. Sigil of the New Dawn triggers, causing you to pay to return Coretapper from your graveyard to your hand
4. Resolve Coretapper's ability, putting two charge counters on Magistrate's Scepter
5. Activate Magistrate's Scepter's second ability by tapping it and removing three charge counters from it, taking an extra turn after this one
6. Cast Coretapper by paying
7. Repeat each turn

Results

• Infinite turns