Prototype Portal, Corridor Monitor, Gilded Lotus, and Panharmonicon

Prerequisites

• Prototype Portal on the battlefield
• Corridor Monitor in exile
• Gilded Lotus on the battlefield
• Panharmonicon on the battlefield

Steps

1. Activate Gilded Lotus by tapping it, adding three mana of any color
2. Activate Prototype Portal by paying and tapping it, creating a token copy of Corridor Monitor
3. The Corridor Monitor token enters the battlefield, untapping Prototype Portal and Gilded Lotus
4. Repeat

Results

• Infinite colored mana
• Infinite creature tokens
• Infinite ETB