Chthonian Nightmare + Pitiless Plunderer + Shambling Ghast + Greedy Freebooter

Chthonian Nightmare

Pitiless Plunderer

Shambling Ghast

Greedy Freebooter

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 Greedy Freebooter or Shambling Ghast and returning Chthonian Nightmare from the battlefield to your hand.
4. When Greedy Freebooter or Shambling Ghast dies, it and Pitiless Plunderer trigger, creating two Treasure tokens.
5. Resolve the Chthonian Nightmare ability, returning either Greedy Freebooter or Shambling Ghast from your graveyard to the battlefield.
6. Activate the Treasures by tapping and sacrificing them, adding 1.
7. Repeat.