Magistrate's Scepter, Contagion Engine, and Lithoform Engine

Prerequisites

• Magistrate's Scepter on the battlefield
• Contagion Engine on the battlefield
• Lithoform Engine on the battlefield
• Magistate's Scepter has at least one charge counter on it
• each turn available

Steps

1. Activate Contagion Engine by paying and tapping it
2. Holding priority, activate Lithoform Engine's first ability by paying and tapping it, copying Contagion Engine's ability
3. Resolve both Contagion Engine abilities, putting four charge counters on Magistrate's Scepter
4. 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
5. Repeat each turn

Results

• Infinite turns