Chthonian Nightmare + Priest of Gix + Fumulus, the Infestation + Umbral Collar Zealot

Chthonian Nightmare

Priest of Gix

Fumulus, the Infestation

Umbral Collar Zealot

How it works

1. Activate Umbral Collar Zealot by sacrificing Priest of Gix.
2. When Priest of Gix dies, Fumulus's first ability triggers, creating a 1/1 Insect creature token.
3. Resolve the Umbral Collar Zealot ability, putting a +1/+1 counter on it.
4. Activate Chthonian Nightmare by paying EEE, sacrificing the Insect 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 clever loop revolves around recycling Priest of Gix to constantly refund and grow your resources, starting with its entry-triggered black mana and the initial energy from Chthonian Nightmare. By using Umbral Collar Zealot to sacrifice the Priest instead of your own resources, you feed Fumulus, the Infestation to immediately generate a sacrificial Insect token. That very token is then fed into Chthonian Nightmare's activation cost—repaying the energy spent, bouncing the enchantment back to your hand, and pulling the Priest right back out of the graveyard to do it all over again.