The Underworld Cookbook, Clock of Omens, Metalwork Colossus, and Stridehangar Automaton

Prerequisites

• The Underworld Cookbook on the battlefield
• Clock of Omens on the battlefield
• Metalwork Colossus in hand
• Stridehangar Automaton on the battlefield

Steps

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

Results

• Infinite self-discard triggers