On their quest to gather all the lost mutagen canisters from the previous episode, the turtles bring a mutant squirrel back to the lair and horror ensues.
This episode provides examples of:
- Body Horror: The squirrels' tongues flail around outside of their mouths and they multiply inside a living organism's stomach.
- Breather Episode: Downplayed. It's a break from the problems that the Turtles and April ran into, and Mikey's comic obsession does add humor to the plot. But the Squirrelanoids and dark environments, however, heighten the creepiness factor of the episode considerably, even if the Squirrelanoids seem to start out fairly cute.
- Expy: See Shout-Out.
- Genre Savvy: Mikey uses his comic book to help defeat the mutant squirrels.
- Donatello notes the cliche ways to "get eaten", as Raphael so eloquently put it whilst dealing with the mutant squirrels.
- Getting Crap Past the Radar: Raph and Mikey act like they're high after eating old pizza.
- Mikey wears old underwear on the outside of his shell.
- Gilligan Cut: Splinter gives a Rousing Speech to his sons asking which of them is brave enough to face the Squirrelanoids. Cut to Metalhead going in their place.
- Killer Rabbit: The Squirrelanoids at first glance look like normal squirrels, but eventually turn into horrific monsters.
- Off with His Head!: The Squirrelanoids decapitate Metalhead.
- Orifice Evacuation: The squirrelanoids force their victims to vomit them out after they asexually reproduce in their hosts stomach. Michaelangelo Lamp Shades this when he says that the aliens in his comic come out of their victims rectums.
- Orifice Invasion: The Squirrelanoids reproduce by forcing themselves down a living being's throat, splitting into two inside the stomach, then forcing their way back out through the mouth.
- Sequel Hook: The Squirrelanoids survived and will be coming out again. Lampshaded before it's shown, even!
- Shout-Out: The mutant squirrels are like lower-rated versions of the alien from Alien, and Mikey's comic is kinda similar too.
Mikey: Game over, man. Game. Over.
- Not to mention him quoting the second Alien movie.
- Vomit Indiscretion Shot: The way the mutant squirrels finish reproducing. This leads to an infected bum vomiting in slow-motion directly into the camera, and later Raphael after he's infected too.