Chthonian Nightmare + Priest of Gix + Skittering Precursor + Phyrexian Altar

Chthonian Nightmare

Priest of Gix

Skittering Precursor

Phyrexian Altar

How it works

1. Activate Phyrexian Altar by sacrificing Priest of Gix, adding one mana of any color.
2. When Priest of Gix dies, Skittering Precursor triggers, creating a 0/1 Eldrazi Spawn creature token.
3. 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.
4. When Priest of Gix enters the battlefield, it triggers, adding .
5. Cast Chthonian Nightmare by paying 1.
6. When Chthonian Nightmare enters the battlefield, it triggers, causing you to get EEE.
7. Repeat.