Chthonian Nightmare + Priest of Gix + Skittering Precursor + Phantom Train

Chthonian Nightmare

Priest of Gix

Skittering Precursor

Phantom Train

How it works

1. Activate Phantom Train by sacrificing Priest of Gix.
2. When Priest of Gix dies, Skittering Precursor triggers, creating a 0/1 Eldrazi Spawn creature token.
3. Resolve the Phantom Train ability
4. Activate Chthonian Nightmare by paying EEE, sacrificing the Eldrazi Spawn and returning Chthonian Nightmare from the battlefield to your hand, returning Priest of Gix from your graveyard to the battlefield.
5. When Priest of Gix enters the battlefield, it triggers, adding .
6. Cast Chthonian Nightmare by paying 1.
7. When Chthonian Nightmare enters the battlefield, it triggers, causing you to get EEE.
8. Repeat.

This delightful loop creates an engine of endless sacrifices and mana by turning graveyard recursion into a self-sustaining cycle. When you activate Phantom Train to sacrifice Priest of Gix, Skittering Precursor steps in to provide a sacrificial Eldrazi Spawn token, which instantly funds the energy cost to loop Chthonian Nightmare back to your hand while dragging Priest of Gix right back out of the graveyard. Every time the priest returns, it replenishes your black mana supply to recast the enchantment, leaving you with infinite black mana and endless sacrifice triggers.