Chthonian Nightmare + Priest of Gix + Skittering Precursor + Carrion Feeder

Chthonian Nightmare

Priest of Gix

Skittering Precursor

Carrion Feeder

How it works

1. Activate Carrion Feeder 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 Carrion Feeder ability, putting a +1/+1 counter on it.
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 loop relies on Chthonian Nightmare's energy generation and recursive ability to continuously cycle Priest of Gix back from the graveyard, while Skittering Precursor turns every sacrifice into the exact fuel you need. By using Carrion Feeder as the outlet to sacrifice Priest of Gix, you trigger the Precursor to create an Eldrazi Spawn token, which Chthonian Nightmare then consumes along with its stored energy to pay its cost and return to your hand. Recasting Chthonian Nightmare replenishes your energy supply via its entrance trigger, and the black mana refunded by Priest of Gix easily pays for the spell, leaving you with a rapidly growing Carrion Feeder and endless triggers.