Underworld Breach + Diligent Excavator + Thassa's Oracle + Phantasmal Image

Underworld Breach

Diligent Excavator

Thassa's Oracle

Phantasmal Image

How it works

1. Cast the artifact creature from your hand by paying 0.
2. Diligent Excavator and Phantasmal Image 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 a zero-mana artifact creature—most commonly, a Memnite or Ornithopter—as its engine of destruction, continuously recurred from the graveyard through Underworld Breach's escape mechanic. While you churn this creature in and out of the graveyard, Phantasmal Image enters as a copy of Diligent Excavator, effectively doubling your milling triggers so that every single loop mills four cards instead of two. As your graveyard swells and your library rapidly dwindles into nothingness, you can finally find and cast Thassa's Oracle, whose enters-the-battlefield trigger sees your empty library and immediately claims the victory.