The air of the Kraang's part of Dimension X is nitrogen mixed with sulfur and that it is very foggy, the air is toxic and cannot be inhaled by humans, animals, and most mutants, only by aliens (Utroms, Triceratons, Salamandrians) and mutants mutated there by The Kraang (Leatherhead, Tiger Claw, Alopex). The water of Dimension X has hydrocarbon that can melt anything in the dimension of Earth. For some reason, the water had no effect on April O'Neil when some of it was accidentally splashed on her. Later revealed to be because she's a human-kraang hybrid.
"It Came From The Depths" - Leatherhead's flashback shows him being mutated and raised in a Kraang lab in Dimension X.
"Showdown, Part 1" and "Booyaka-Showdown, Part 2" - The Kraang can be seen contacting their leader Kraang Prime who came to Earth from Dimension X in order to terraform it so the Kraang to live in our dimension.
"The Wrath of Tiger Claw" - Tiger Claw's flashback shows him battling through various dimensions.
"Plan 10" - Raphael takes a glance at the Kraang plans for the invasion.
"Into Dimension X" - It's revealed that time passes faster in Dimension X than on Earth, Mikey gets stuck in there for "months" and Leatherhead gets older after staying in Dimension X for "decades". It's also revealed where the Kraang Power Cell comes from and that a lot of stuff in Dimension X reacts to sound.
"Battle for New York, Part 1"- April states that she's had dreams about the mutated humans who the kraang have captured and are forcing them to work for them a vision from one of her dreams is briefly seen as she states this.
"Battle for New York, Part 2"- With help from The Mighty Mutanimals, the turtles use the The Turtle Blimp to enter so they can find, de-mutate and return all of the humans to New York City. Unbeknownst to all of them, Kraang Subprime secretly followed them. Mikey then puts on his Savage suit on and using his organic antenna points his brothers in the direction that their in. while searching, they are attacked by a Kraathatrogon who crashes the blimp which results in it being destroyed and the turtle ending up on a nearby floating island. luckily, Mikey manages to fend off the creature by hitting it's weak spot which is it's butt face. They then spot and locate the hybrid human on another nearby floating island. they come up with a plan to save them and prepare to steal a Kraang Stealth Ship so they can make their way to a nearby Technodrome which is full of mutagen that they can convert into Retro-Mutagen and de-mutate the humans. suddenly Kraang Subprime appears and Mikey manages to easily knock him away which gives them a chance to escape. Kraang Subprime then contacts the kraang at high base and orders them to release the Dracodroid which attacks the turtles ship causing them to crash into the Technodrome that their heading to. luckily hey get in and start to fight their way to the control room where they dispose of all of the kraang with Donnie discovering that the kraang use mutagen to power the Technodrome itself.Kraang prime tries to break in by cutting through the door as Mikey succeeds on altering the fuel converters after Donnie converts the mutagen and the ship stops working. The Mutanimals then help teleport the humans back too earth after the turtles de-mutate them island after island. they then escape by being teleported as well as they hold off the kraang and Subrprime after saving the humans. Kraang Subprime then begins to scream about his failure of taking out the turtles as the Technodrome begins to head into a giant asteroid-like rock which it crashes into and explodes into nothing. all of the kraang are then teleported back into Dimension X after this.
- Bioelectric Beings
- The Kraang
- Tiger Claw
- The Newtralizer
- Rock Soldiers
- Sea Monster
- The "TCRI" episode is the only one to show Dimension X's air being green, in every other episode it has a pink coloration to it.