While Donatello examines a pair of mysterious crystals, the lair's perimeter alarm is triggered after the crystals begin to glow. The Turtles investigate and find tracks indicating the presence of some unknown creature. These tracks lead them deep underground where they uncover an abandoned Foot Genetics lab.
First appearance of Quarry, Stonebiter, Razorfist and the rest of the underground dwellers
This episode provides examples of:
- Apocalyptic Log: The Foot's video archives
- Deadly Road Trip: Specifically the kind where the group are trapped in a cave (alright, underground) and being pursued by monsters.
- Everyone Has Standards: Raphael is visibly outraged by the footage of the Foot experimenting on some poor guy.
- Foreshadowing: The Apocalyptic Log mentions that the mutant slaves discovered an underground settlement unrelated to Shredder's enemies. That settlement becomes very important in Part 3, as well as one of the show's secondary Story Arcs. Mikey also has a prophetic dream, in which he visits a strange settlement and encounters something ominous.
- From Bad to Worse: The Turtles are unnerved to see the Apocalyptic Log in full. Just when it's done, they hear growling noises in the dark and realize they've now got company.
- Genre Savvy: From the moment the Turtles find that something ripped through solid cement, Mikey begins citing horror movie tropes, such as the dangers of not knowing a monster's weakness before it's too late
- It Can Think: The monsters. The Foot thought they had only primitive intelligence after the experiments, but they were merely biding their time.
- Lampshade Hanging: As the Turtles see footage of the Foot transforming people into monsters.Michelangelo: This is starting to get really weird.
Raphael: Starting? - Meaningful Echo: Michelangelo repeatedly echoes the line from the monster movie he was watching at the start of the episode. Later, the Foot Scientist in the video archives says the same line, only this time it applies to 'real life', not just a movie.
- Mythology Gag: Stonebiter has some visual similarity to Complete Carnage, a minor villain from the Mirage comics.
- No Sympathy: The Foot scientists in the Apocalyptic Log show no concern to anyone who have mutated into monsters. They simply dismiss the pain one person is suffering as "a minor annoyance".
- Obfuscating Stupidity: As the monsters exact their revenge, the lead scientist realizes they were fully intelligent the entire time and just playing dumb to wait for the right time to escape.
- Oh, Crap!: After seeing the Apocalyptic Log and hearing some strange noises in the dark, Mikey freaks and runs away. Raph hates to admit it, but he agrees.
- Pay Evil unto Evil: The underground dwellers are fairly benevolent creatures, but after getting free they enacted brutal revenge upon the scientists who'd enslaved and mutated them.
- Power Crystal/ Power Glows: the energy crystals
- Scream Discretion Shot: The Apocalyptic Log's camera is crushed, just as the lead doctor screams from off-screen.
- Screw This, I'm Outta Here: Panicked over the growling noises in the dark, Mikey says there's always one guy in the monster movie who advocates this and immediately does so himself. Raphael agrees that it's time to book it.
- Strapped to an Operating Table: The Foot's "volunteers" in the video archive footage.
- That Came Out Wrong: When the Turtles spot a flash of movement on a camera, this exchange occurs:Raph: Sewer rats are getting bigger.
Mikey: Yeah, time to cut the cheese.
[Leo gives him a look and shakes his head]
Mikey: [sheepishly] That's not what I meant. - These Are Things Man Was Not Meant to Know: The line appears in Mikey's movie and reappears in the Apocalyptic Log.Mikey: That's the one line in a monster movie you don't wanna hear.
- To Be Continued: Lampshaded, as the episode ends with the Turtles faced with three monsters.Mikey: Guys, this isn't the end of the movie, is it?
- Understatement: The lead Foot scientist observes the transformation involves "some discomfort" and what "a minor annoyance" that is, all as the poor guy screams and convulses in agony.
- Wall Crawl: While checking what tripped the perimeter alarm, Donatello finds tracks all over a tunnel.
- Wham Shot: The Foot's logo appearing on the monitor.
- You Have Outlived Your Usefulness: With the settlement not having anything to do with his enemies, the Shredder orders the project shut down and the monsters killed. The monsters, however, had other ideas.
