Chthonian Nightmare | Eternal Witness | Time Warp

Cards

Eternal Witness in your graveyard.
Chthonian Nightmare and
Time Warp in hand.
You control a nontoken creature with mana value 3 or less.
({3} magic symbol) ({U} magic symbol) ({U} magic symbol) the first turn, with ({5} magic symbol) ({U} magic symbol) ({U} magic symbol) ({B} magic symbol) ({B} magic symbol) each extra turn available.

Cast
Time Warp by paying ({3} magic symbol) ({U} magic symbol) ({U} magic symbol) , causing you to take an extra turn after this one.
Move to your next turn.
Cast
Chthonian Nightmare by paying ({1} magic symbol) ({B} magic symbol) .
When
Chthonian Nightmare enters the battlefield, it triggers, causing you to get ({E} magic symbol) ({E} magic symbol) ({E} magic symbol) .
Activate
Chthonian Nightmare by paying ({E} magic symbol) ({E} magic symbol) ({E} magic symbol) , 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.
When
Eternal Witness enters the battlefield, it triggers, returning
Time Warp from your graveyard to your hand.
Cast
Chthonian Nightmare by paying ({1} magic symbol) ({B} magic symbol) .
When
Chthonian Nightmare enters the battlefield, it triggers, causing you to get ({E} magic symbol) ({E} magic symbol) ({E} magic symbol) .
Activate
Chthonian Nightmare by paying at most ({E} magic symbol) ({E} magic symbol) ({E} magic symbol) , 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.
Repeat.