Chthonian Nightmare + Priest of Gix + Fumulus, the Infestation + Altar of Dementia

Chthonian Nightmare

Priest of Gix

Fumulus, the Infestation

Altar of Dementia

How it works

1. Activate Altar of Dementia 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 Altar of Dementia ability, causing target player to mill cards equal to Priest of Gix's power.
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 loop turns the initial energy from Chthonian Nightmare into an endless cycle of shadowy resurrection, perfectly sustained by the dark ritualistic mana of Priest of Gix. As you repeatedly sacrifice the Priest to Altar of Dementia to mill away your opponent's library, Fumulus, the Infestation catches every single creature sacrifice to instantly swarm the board with flying Insect tokens. Those very same tokens then provide the fodder needed to bounce and recast Chthonian Nightmare, fueling the engine indefinitely without ever running out of energy or black mana.