Chthonian Nightmare + Eternal Witness + Notorious Throng

Chthonian Nightmare

Eternal Witness

Notorious Throng

How it works

1. Deal combat damage using a Rogue
2. Cast Notorious Throng for its prowl cost by paying 5, causing you to take an extra turn after this one.
3. Move to your next turn.
4. Cast Chthonian Nightmare by paying 1.
5. When Chthonian Nightmare enters the battlefield, it triggers, causing you to get EEE.
6. Activate Chthonian Nightmare by paying EEE, sacrificing a creature with mana value 3 or less, and returning Chthonian Nightmare from the battlefield to your hand, returning Eternal Witness from your graveyard to the battlefield.
7. When Eternal Witness enters the battlefield, it triggers, returning Notorious Throng from your graveyard to your hand.
8. Cast Chthonian Nightmare by paying 1.
9. When Chthonian Nightmare enters the battlefield, it triggers, causing you to get EEE.
10. Activate Chthonian Nightmare by paying at most EEE, sacrificing Eternal Witness, and returning Chthonian Nightmare from the battlefield to your hand, returning a creature with mana value 3 or less from your graveyard to the battlefield.
11. Repeat.

This cunning loop leverages the extra turn granted by Notorious Throng to set up an endless engine of recursion. By casting Chthonian Nightmare, its energy-generation ability fuels the enchantment's activation to sacrifice a creature and pull Eternal Witness out of your graveyard, which in turn lets you retrieve Notorious Throng to be recast on your next turn. Because Chthonian Nightmare bounces itself back to your hand as part of the cost, you can endlessly replay it to cycle through your threats while looping your extra turns indefinitely.