Chthonian Nightmare + Impulsive Pilferer + Shambling Ghast + Skittering Precursor

Chthonian Nightmare

Impulsive Pilferer

Shambling Ghast

Skittering Precursor

How it works

1. Cast Chthonian Nightmare by paying 1.
2. When Chthonian Nightmare enters the battlefield, it triggers, causing you to get EEE.
3. Activate Chthonian Nightmare by paying an amount of E, sacrificing Impulsive Pilferer or Shambling Ghast and returning Chthonian Nightmare from the battlefield to your hand.
4. When Impulsive Pilferer or Shambling Ghast dies, it and Skittering Precursor trigger.
5. Resolve the Impulsive Pilferer or Shambling Ghast trigger, creating a Treasure token.
6. Resolve the Skittering Precursor trigger, creating a 0/1 Eldrazi Spawn creature token.
7. Resolve the Chthonian Nightmare ability, returning either Impulsive Pilferer or Shambling Ghast from your graveyard to the battlefield.
8. Activate the Eldrazi Spawn by sacrificing it, adding C.
9. Activate the Treasure by tapping and sacrificing it, adding .
10. Repeat.