The Underworld Cookbook + Clock of Omens + Metalwork Colossus + Stridehangar Automaton

The Underworld Cookbook

Clock of Omens

Metalwork Colossus

Stridehangar Automaton

How it works

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.

This clever loop transforms The Underworld Cookbook into an engine for infinite self-discard by using its ability to put Metalwork Colossus straight into the graveyard while spawning artifacts. Thanks to Stridehangar Automaton's replacement effect, each time you make a Food token you also get an extra Thopter token, giving you the exact pair of artifacts needed to feed into Clock of Omens and untap the Cookbook for another go. Finally, Metalwork Colossus uses those very same sacrificed artifacts to bounce itself right back to your hand, ready to be discarded all over again.