The Underworld Cookbook, Clock of Omens, Metalwork Colossus, and Worldwalker Helm

Prerequisites

• The Underworld Cookbook on the battlefield
• Clock of Omens on the battlefield
• Metalwork Colossus in hand
• Worldwalker Helm on the battlefield

Steps

1. Activate The Underworld Cookbook's first ability by tapping it and discarding Metalwork Colossus, creating a Map and a Food token
2. Activate Clock of Omens by tapping the Food and Map, untapping The Underworld Cookbook
3. Activate Metalwork Colossus by sacrificing the Food and Map, returning it from your graveyard to your hand
4. Repeat

Results

• Infinite self-discard triggers