During a school trip to the zoo's polar bear exhibit, Gretel gets informed on a robbery, which she decides to confront alone since Hamster and Kevin are sick, and Fred is out of town. This proves to be challenging when the villain happens to be a geneticist with the ability to multiply herself.
Tropes:
- An Aesop:
- Think before you do.
- If you can't handle everything on your own, it's okay to ask your friends for help.
- Body of Bodies: At one point, the Marys combine into one giant body to attack Gretel.
- Chain of People: The Marys stand on top of each other to catch Gretel as she tries to fly away.
- Chekhov's Gun: The lever on the polar bear exhibit, which opens the roof of the complex (and is not supposed to be opened because it wastes air conditioning) is crucial to the plan to stop Mary Mitosis.
- Feed It with Fire: Gretel's usual approach of punching foes doesn't work on Mary, since the kinetic energy of the punches just makes her divide further. Gretel eventually figures out that extreme cold would cause all the Marys to recombine into the original.
- I Surrender, Suckers: Gretel pretends to give up and the Marys combine around her into a sphere to trap her. Unfortunately for them, this was Gretel's plan all along, as she carries them to the polar bear enclosure at the zoo, where the cold causes them to recombine into the original Mary.
- Pathetically Weak: Kevin and Hamster are so sick they can't even muster the strength to reach for the TV remote a couple of feet in front of them.
- Screw the Rules, I'm Doing What's Right!: Bailey happily follows and reminds the rules given by the zoo tour guide, but will also happily break one of them to help out Gretel.
- Shout-Out: Bailey's confrontation with the guide when trying to pull the lever for the exhibit's roof is nearly a word-for-word simile to the confrontation between Anakin and Obi-Wan near the end of Revenge of the Sith.
- Sick Episode: Hamster and Kevin are this episode's victim to this trope. They tell each other how terrible they feel like, and each telling gets lengthier and more ridiculous-sounding.
- Self-Duplication: Mary Mitosis is a geneticist who experimented on herself, giving her the ability to duplicate herself when gathering enough kinetic energy. Gretel's punching brings enough heat to speed up the process tremendously.
