When earthquakes start happening around New York, the Turtles, April, and Casey go investigate what's causing them. Meanwhile, The Shredder comes back from his trip to Japan with a new accomplice: Tiger Claw.
This episode is also known as "Wormquake!" in several episode guides and broadcasting networks.
This episode contains examples of:
- A Truce While We Gawk: When April and Casey show up in the middle of the fight between the turtles and the Foot riding a Kraathatrogon, everybody stops fighting and looks at them.
- Art Shift: The '87 universe is 2D animated, in comparison to the show's CGI.
- Beast with a Human Face: April and Casey encounter giant worms brought from Dimension X, and are freaked out by a baby worm that has a human baby's face.
- Big Brother Instinct: Leo succumbs to Tiger Claw's requests to summon Splinter when he's about to drop Mikey in a furnace and when they're back in the lair, Leo's the one wrapping bandages around Mikey's injured arm.
- Big Damn Reunion: The Foot is reunited and reorganized in this episode upon Shredder's return, with newcomer Tiger Claw as The Dragon.
- Brick Joke: The Kraathatrogon ends up in the 1987 universe, which was briefly shown in the first part.
- The Bus Came Back: Shredder, Rahzar, Stockman, and Fishface all return after being absent for several episodes, though Shredder was the only one with an excuse: being in Japan.
- Demoted to Dragon: As she was acting as head of the Foot while Shredder was away, Karai expected to carry on as Shredder's right hand. However, with a new powerful mercenary, and after her own foolishness during his time away, Shredder instead gives Tiger Claw control of the Foot.
- Disney Villain Death:
- Tiger Claw is eaten by a Kraathatrogon which is then teleported to the 1987 universe, though considering Casey survived, it was probably non-fatal.
- Karai also gets one after Leo fails to catch her from falling, though she is shown to have survived in the ending.
- Dude, Where's My Respect?: Karai feels this way when Shredder appoints Tiger Claw as his new second-in-command.
- Even Evil Has Standards: Karai stops Shredder from killing Splinter while he's poisoned and chained up, stating that it's better to beat him in a fair fight. Surprisingly, Tiger Claw agrees. Despite the fact ''they'' were the ones responsible for poisoning him in the first place.
- Evolving Credits: The intro has once again been altered starting with this episode. More specifically in the Rogues Gallery section Mrs. Campbell, Snakeweed, Spider Bytez, the Rat King, and Dog Pound have been removed and replaced with a Squirrelanoid, Slash, Mutagen Man, Rahzar and Tigerclaw. Also the scene with the Turtles fighting Kraang Droids before climbing on top of a building is replaced with them firing grappling hooks and using them as zip lines.
- I Surrender, Suckers: Donnie, April, and Casey are captured by the Kraang. Donnie tells them to go along with it until they're back in their dimension.Casey: For the record, I don't consider this a surrender!
- Ice-Cream Koan: When Leo tells Splinter that he told Karai the truth, Splinter gives one of his wise Splinterisms that may or may not be just him getting his anger across.Splinter: There is a saying. "He who runs his mouth gets face full of nunchaku."
Leo: They say that in Japan?
Splinter: They would if you were there. - Just Desserts: Tiger Claw gets eaten by a Kraathatrogon, but considering Casey's survival, it's unlikely to be permanent.
- Made of Iron: Tiger Claw says this of Splinter, who survived being poisoned.
- Meet Your Early-Installment Weirdness: The Turtles peek through a portal and see their 1987 counterparts, with Mikey asking why they look like dorks.
- Milking the Giant Cow: Kurtzman uses this as an analogy to the Kranng milking mutagen from the Kraathatrogons, complete with the arm gesture.
- Mythology Gag: The title is the same as the 3rd NES game.
- The current interpretation of the Turtles encountering their 1987 counterparts? Why does that sound awfully familiar?
- 80's Leo and 80's Mikey are deliberately Off-Model in the final shot.
- When Casey beats up a Kraang, he says "When you play cricket, you gotta have crumpets.", a reference to one of Raph's lines in the original TMNT movie.
- Several times April screams in a way not unlike her 1987 counterpart.
- The Multiverse: Apparently canonical as of Turtles Forever.
- Nice Job Fixing It, Villain: The earthquakes caused by the Kraathatrogon allowed the turtles to save Splinter from the Foot and one of the Kraathatrogons swallows Tiger Claw.
- Panthera Awesome: Tiger Claw, a mutated tiger.
- Papa Wolf: Splinter shows his fatherly side to the turtles and tries to do the same thing for Karai.
- Screw This, I'm Out of Here!: Stockman can be seen fleeing the room while the Foot tries to stop the Turtles from escaping with Splinter.
- Shout-Out:
- Hundreds of meters-long triple-jawed worms that can be ridden and controlled by two rope-like appendages? Donatello even uses a rhythmic vibration to attract the worm to his location. All we need is Casey being the Kwizatz Haderach.
- Casey being swallowed alive and trapped in the worm's belly, as well as a few other shots, bring to mind the Tremors movies.
- Kurtzman saying "Great Caesar's ghost", much like Perry White.
- "UNLEASH THE KRAATHATROGON!!"
- Unusually Uninteresting Sight:(after being introduced to Rahzar's new form) Shredder: You look terrible, Bradford.
- Villainous Friendship: Fishface tries to stir up one with Tiger Claw by getting him some skim milk.
- Wham Episode:
- Karai is told she's really Miwa and by the end she's starting to wonder if it's true.
- There's also the fact that the mutagen the Kraang are always carrying around is actually Kraathatrogon milk.
- What the Hell, Hero?: Raph directs this towards Leo, stating it was his fault Splinter was captured and gets this treatment from the viewers ignoring the fact that, if not for Splinter, he and his brothers would've fallen into the furnace.
- Witch with a Capital "B": April calls Karai an evil witch.
