When Raph accidentally damages a Kraang machine, it allowed him to switch brains with a Kraang. Now he must find a way to convince his brothers and Splinter that it's really him, before the Kraang controlling his body destroys his brothers or worse, reveals their location to the rest of the Kraang.
- Aliens Speaking English: A rare variant where Raph is speaking without the mechsuit, though it could be him just speaking in the Kraang's language (we heard him making the Kraang's usual sounds when out of the suit).
- Can't Kill You, Still Need You: Raph fights the Kraang he was body swapped with, but stops short of stabbing him in the face because he realizes he'd just be stabbing himself.
- Continuity Nod: The Kraang aquatic monster returns (along with its lusting for the T-Sub).
- Foreshadowing: Not only are the Kraang planning a second invasion, but Donatello has a plan to fight back that is shown at the end of the episode. A turtle Mecha.
- "Freaky Friday" Flip: The plot point (With the Kraang wanting to switch the mind with the world leader, and were in the testing stages when it occured.)
- Friendly Tickle Torture: Mikey's response to try and get a reaction out of Raph (whose mind had been brainswapped by the Kraang) is tickling him. Kraang-Raph gives a VERY flat response.
- Idiot Ball: Leo, Mikey, and Donnie hold it in the episode's opener. Despite having just witnessed the Kraang device and seen that it swaps the minds of those who are caught in its beam, they still carry Raph off obliviously after both he and a random Kraang are caught in the very same beam.
- Man, I Feel Like a Woman: Casey starts pinching April's butt after they switch minds. And the first thing he does when they switch back is feel his own chest, unhappy.
- Mythology Gag: Donnie describes the T-Sub as "turtle power(ed)". Given that it's Donnie who says it, doubles as an Actor Allusion.
- Shout-Out:
- While running from the Kraang after ejecting from his robot shell, Raph goes "Nuh nuh nuh" and "whoop whoop whoop" in a manner similar to Curly. (Or, since he's now an alien organism, Dr. Zoidberg)
- The plot here is similar to the plot of the '87 series episode "The Old Switcheroo".
- The title is likely a reference to Plan 9 from Outer Space.
- Take That!: The scene where Casey is watching anime has him remark that he hates dubbed anime, a clear jab at people who prefer watching anime in Japanese.
- Villains Blend in Better: Inverted. Raphael, despite being somewhat clumsy operating the Kraang suit, at least manages to blend in by replicating the Kraang speech patterns. On the other hand, the Kraang in Raphael's body doesn't make any effort to hide his identity, nor he remains hidden in the street despite being a giant turtle now.
- Voices Are Mental: Somehow, the computerized voice of a Kraang exosuit qualifies as this.
