Chthonian Nightmare + Temporal Manipulation + Timeless Witness

Chthonian Nightmare

Temporal Manipulation

Timeless Witness

How it works

1. Cast Temporal Manipulation by paying 3, causing you to take an extra turn after this one.
2. Move to your next turn.
3. Cast Chthonian Nightmare by paying 1.
4. When Chthonian Nightmare enters the battlefield, it triggers, causing you to get EEE.
5. Activate Chthonian Nightmare by paying EEEE, sacrificing a creature with mana value 2 or less, and returning Chthonian Nightmare from the battlefield to your hand, returning Timeless Witness from your graveyard to the battlefield.
6. When Timeless Witness enters the battlefield, it triggers, returning Temporal Manipulation from your graveyard to your hand.
7. Cast Chthonian Nightmare by paying 1.
8. When Chthonian Nightmare enters the battlefield, it triggers, causing you to get EEE.
9. Activate Chthonian Nightmare by paying at most EE, sacrificing Timeless Witness, and returning Chthonian Nightmare from the battlefield to your hand, returning a creature with mana value 2 or less from your graveyard to the battlefield.
10. Repeat.

This ingenious loop revolves around recycling Chthonian Nightmare's energy-fueled resurrection ability to continuously exploit ETB triggers. By sacrificing a creature with mana value 2 or less to return Timeless Witness from your graveyard, you immediately trigger the Witness to pull Temporal Manipulation back to your hand. Replaying Temporal Manipulation then grants you the infinite turns you need, while the eternalize mechanic and your renewable energy supply ensure you have a constant stream of fodder and resources to keep the cycle spinning.