The Cosmic Ocean
Teenage Mutant Ninja Turtles (2012 TV Series) episode
Title screen
Season Code: 409
Episode: 87
Original airdate March 13, 2016
Written by Mark Henry
Producers: Brandon Auman
Directed by Sebastian Montes
Voice Direction Andrea Romano
Episode chronology
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"The War for Dimension X" "Trans-Dimensional Turtles"

Teenage Mutant Ninja Turtles Season 4
October 25, 2015 - February 26, 2017
List of Teenage Mutant Ninja Turtles episodes


  1. Beyond The Known Universe
  2. The Moons of Thalos 3
  3. The Weird World of Wyrm
  4. The Outlaw Armaggon!
  5. Riddle of The Ancient Aeons
  6. Journey to the Center of Mikey's Mind
  7. The Arena of Carnage
  8. The War for Dimension X
  9. The Cosmic Ocean
  10. Trans-Dimensional Turtles
  11. Revenge of the Triceratons
  12. The Evil of Dregg
  13. The Ever-Burning Fire
  14. Earth's Last Stand
  15. City at War
  16. Broken Foot
  17. The Insecta Trifecta
  18. Mutant Gangland
  19. Bat in the Belfry
  20. The Super Shredder
  21. Darkest Plight
  22. The Power Inside Her
  23. Tokka vs. The World
  24. Tale of Tiger Claw
  25. Requiem
  26. Owari

Season 1Season 2 - Season 3 - Season 4 - Season 5

"The Cosmic Ocean" is the ninth episode of the fourth season of the 2012 TV series, and is the eighty-seventh episode overall in the series. It first aired on March 13th, 2016.


The Turtles journey through an ocean-like area of space, and they must prove themselves worthy if they are to retrieve the second piece of the Black Hole Generator.


Major Characters

Minor Characters


On the Holodeck of the Ulixes, Leonardo speaks to the hologram of Master Splinter to gain solace and advice from him before returning to the bridge as they arrive at the Cosmic Ocean of Varuna, location of the second piece of the Black Hole Generator according to the information they received from Bishop and the Utrom Queen. However, unknown to the gang, Armaggon has finally caught up to them, and is looking for both a little payback and his bounty from Lord Dregg.

As the Ulixes passes through the ocean, they soon encounter the guardians of the second piece, the Daagons, however, they take the Turtles to be hostile, until the Fugitoid presents the symbol of the Utroms to them, at which point they stand down in respect to the Utrom symbol, and take the gang to their leader, Hiidrala, who wonders why they have come. As the Turtles explain their situation, Hiidrala reveals that the second piece will only be granted to them if they prove themselves worthy against its guardian, Cthugga, who only responds to her. If it deems them worthy, it will hand over the piece without resistance, if it doesn't, they will be consumed by it.

As the gang make their way to the Cthugga's location in the Ulixes, the ship is attacked by Armaggon, who manages to get aboard and take Leo hostage after a scuffle, intending to not only collect his bounty, but deliver the Black Hole Generator pieces to Lord Dregg. With Armaggon having commandeered the Ulixes, they continue onward to the Cthugga's location, but as April detects it with her psychic powers, it soon attacks, knowing that they are unworthy, and chases them back out into the asteroids where it resides. They manage to lose it, and soon the Daagons arrive to subdue and arrest Armaggon, as the Fugitoid had sent out a distress call when Armaggon commandeered the Ulixes.

Unfortunately, upon returning to Hiidrala's throne room, it is clear that the Turtles have failed, so they will never get the second piece. As they try and plea for another chance, Armaggon soon starts laughing, revealing that reinforcements have arrived, in the form of Lord Dregg and several of his Vreen drones. With that, the Turtles, April, Casey, the Daagons, and Hiidrala engage Dregg and his Vreen in battle, with Armaggon soon joining when Dregg frees him from his chains. As the battle continues, Dregg soon turns his attention to Hiidrala, and after using one of his claws to cover her face, prepares to finish her off with a missile from his chest launcher.

Seeing her in danger, Leo throws himself in the path of the missile, saving Hiidrala's life. Once she gets Dregg's claw off her face, she is furious, and summons Cthugga, who manages to grab and swallow Dregg and Armaggon whole. Without Dregg to command them, the Vreen lose the will to fight and flee. Afterwards, as Hiidrala thanks Leo for saving her life, that proves to her that the Turtles are worthy, and has her Daagons bring forth the second piece of the Black Hole Generator, having kept it locked in her vaults this whole time. Trusting that the Turtles can destroy the infernal device, Hiidrala declares them honorable heroes of the Daagons, earning their respect and support should they need it.

With two pieces in their possession, the gang depart the Cosmic Ocean of Varuna to head after the final piece. However, the Fugitoid has his doubts on how he can destroy the device, but while April is saddened to leave the beautiful location, Raphael is relieved to know they won't be dealing with Dregg and Armaggon anymore.

Back where Cthugga is slumbering, Dregg's ship the Hornitron arrives and launches dozens of Vreen eggs into its mouth. Soon, the guardian opens its mouth to release the hatched drones, who escape with Armaggon and Dregg in tow. As Cthugga retreats deeper into its lair, Dregg enters the cockpit of the Hornitron with an evil chuckle, and together with Armaggon, make good their escape as Dregg swears he will get his vengeance, while Armaggon laughs victoriously as well as he also has a bone to pick with the Turtles.


  • The electrical seaweed, that Raph warned about, was referenced from an underwater level in the 1989 video game for the NES. Fugitoid's reference to how fast he could make it through (two minutes, twenty seconds) is the time limit given in that stage.
  • The image Mikey thinks up in which he imagines what Cthugga would look like, is character art of the Archie version of Ray Fillet.
    • This is the second homage to Ray Fillet in the series, the first being his silhouette in a food can at Bernie's General in the episode "In Dreams".
  • The names Daagon and Cthugga are based on Dagon and Cthulhu of H. P. Lovecraft's writings.
    • Cthugga's appearance was based on Dagon's.
  • The Daagon are based and nicknamed after Merdude, a character from the 1987 TV series.
  • When being chased by Cthugga, Leo tells Fugitoid "we need more speed". Fugitoid replies in a Scottish accent "I'm giving her all she's got, Captain!" This is a reference to the popular catchphrase by Chief Engineer Scotty on Star Trek: The Original Series. In this exchange, Leo acts as Captain Kirk.
  • It's revealed that the Sea Monster used by the Kraang to protect their underwater base in the first season comes from the cosmic ocean of Varuna, not Dimension X, as they're used as mounting by the Daagon.
  • The character Hiidrala seems to be inspired by Hydras, not the many-headed serpent in Greek mythology, but the genus of small, fresh-water animals.
    • Much like Hiidrala, the Hydras have multiple tentacles and are generally sedentary or sessile, but do occasionally move quite readily.
    • Biologists are especially interested in Hydra because of their regenerative ability – they appear not to age or die of old age.


The Cosmic Ocean/Gallery


The Cosmic Ocean/Transcript

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