Underworld Breach + Stitcher's Supplier + Infernal Plunge + Prismite

Underworld Breach

Stitcher's Supplier

Infernal Plunge

Prismite

How it works

1. Cast Infernal Plunge for its escape cost by paying , exling three other cards from your graveyard, and sacrificing Stiticher's Supplier.
2. When Stitcher's Supplier dies, it triggers, causing you to mill three cards.
3. Resolve Infernal Plunge, adding .
4. Activate Prismite by paying 2, adding .
5. Cast Stitcher's Supplier for its escape cost by paying and exling three other cards from your graveyard.
6. When Stitcher's Supplier enters the battlefield, it triggers, causing you to mill three cards.
7. Repeat.

This clever loop turns Underworld Breach into an engine for infinite self-mill by continuously recycling creatures right out of your graveyard. You kick things off by sacrificing Stitcher's Supplier to pay for Infernal Plunge, which triggers the Supplier to mill three cards upon dying while netting you a burst of red mana. Prismite steps in as a vital color-fixer, converting that red mana into black so you can pay the escape cost to cast Stitcher's Supplier straight back from the graveyard. As the Supplier enters the battlefield, it mills three more cards to constantly refill your graveyard with fuel, allowing you to seamlessly loop your spells over and over again.