Prototype Portal, Retreat to Coralhelm, Ensoul Artifact, and Ancient Den

Prerequisites

• Prototype Portal on the battlefield
• Retreat to Coralhelm on the battlefield
• Ensoul Artifact on the battlefield
• Ancient Den in exile

Steps

1. Activate Prototype Portal by tapping it, creating a token copy of Ancient Den
2. When the Ancient Den token enters the battlefield, Retreat to Coralhelm triggers, untapping Prototype Portal
3. Repeat

Results

• Infinite colored mana
• Infinite Forest tokens
• Infinite Plains tokens
• Infinite Island tokens
• Infinite Mountain tokens
• Infinite Swamp tokens
• Infinite landfall triggers
• Infinite copies of a specific land