Underworld Breach + Diligent Excavator + Thassa's Oracle + Hulking Metamorph

Underworld Breach

Diligent Excavator

Thassa's Oracle

Hulking Metamorph

How it works

1. Cast the artifact creature from your hand by paying 0.
2. Diligent Excavator and Hulking Metamorph trigger, causing you to mill four cards.
3. The artifact creature enters the battlefield and dies as a state-based action due to having zero toughness.
4. Cast the artifact creature from your graveyard for its escape cost by paying 0 and exiling any three cards from your graveyard, except Thassa's Oracle if it is in your graveyard.
5. Repeat from step 2 until you have an empty library.
6. If Thassa's Oracle is in your hand, cast it by paying .
7. Otherwise, cast Thassa's Oracle from your graveyard for its escape cost by paying and exiling three cards from your graveyard.
8. Thassa's Oracle enters the battlefield, causing you to win the game.

This clever loop relies on Underworld Breach to grant escape to everything in your graveyard, turning your bin into a recursive engine fueled by your own cards. As you repeatedly cast Hulking Metamorph for zero mana by copying zero-cost artifact creatures or utilizing cost reductions, Diligent Excavator turns each cast into a self-milling trigger that fuels the escape costs over and over again. Once your entire library has been successfully binned, you simply find and cast Thassa's Oracle—either normally or from the graveyard via Underworld Breach—and let its enters-the-battlefield trigger check your devotion and win you the game on the spot.