Chthonian Nightmare + Temporal Manipulation + Shipwreck Dowser

Chthonian Nightmare

Temporal Manipulation

Shipwreck Dowser

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 EEEEE, sacrificing a creature with mana value 1 or less, and returning Chthonian Nightmare from the battlefield to your hand, returning Shipwreck Dowser from your graveyard to the battlefield.
6. When Shipwreck Dowser 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 E, sacrificing Shipwreck Dowser, and returning Chthonian Nightmare from the battlefield to your hand, returning a creature with mana value 1 or less from your graveyard to the battlefield.
10. Repeat.

This cunning loop uses Chthonian Nightmare as a repeatable engine that funds its own energy costs while continually looping Shipwreck Dowser from the graveyard. Each time Shipwreck Dowser returns, its enter-the-battlefield trigger salvages Temporal Manipulation from your graveyard back to your hand, allowing you to cast the extra-turn spell repeatedly. Because Chthonian Nightmare's ability lets you recycle sacrifices and energy, you can secure infinite turns and total control of the game.