The Magic School Bus Makes a Stink
A smell competition is being held at Walker Elementary, but Carlos can only find mothballs. Just as he thinks it will help him pass, Janet steps on it; she apologizes but it's not clear if she did it by accident or on purpose. The class comes together to combine their scented objects into the perfect smell, while learning about scent molecules.
- Call-Back: Dorothy Ann mentions how when rebuilding a sugar crystal, the class learned that molecules make up everything in the world.
- Cheaters Never Prosper: Janet tries to sabotage the class's winning smell, after they worked hard to create it, but the bus fortunately has equipment that can destroy scent molecules. They also make it clear to her after they win that they know Janet attempted sabotage.
- Everyone Has Standards: Sometimes, when Carlos makes a joke, Ms. Frizzle will laugh along and say something among the lines "Oh, good one Carlos!" But even she looks visibly disgusted at his "Snot Funny" joke.
- Et Tu, Brute?: Arnold's at first in denial that his cousin would sabotage the class's submission to the smell contest.
- "Fantastic Voyage" Plot: The class goes inside Janet's nose to further see how smell molecules work.
- Foreshadowing: Keesha says she's not surprised when Janet crushes Carlos's mothball, even though Janet looked genuinely sorry about it. Later on Janet sabotages the class's winning smell by adding the skunk aroma.
- I Know You Know I Know: At the end after they win, Carlos mentions skunk smell offhand to Janet, who gains a Luminescent Blush.
- I Was Just Joking: Ralphie cheerfully adds his gym socks to the large scent bottle after the class adds mint, roses, and a banana. Carlos then smells it and realizes that the gym socks make the difference. Flora Whiff agrees.
- Mundane Object Amazement: Carlos hopes to invoke this in the beginning by providing a mothball for Flora Whiff to smell. Janet then steps on it.
- No Plans No Prototype No Back Up: Justified as the class had only made it with a few hours to spare for the competition and with no time to make another, but after Janet adds skunk spray to their smell, no one thinks to recreate the same formula with a rose, cinnamon, banana, mint, and Ralphie's second gym sock.
- Strange Minds Think Alike: According to Carlos, "half the class brought cinnamon."
- Took a Level in Jerkass: Usually Janet is a Jerk with a Heart of Gold, but this is the only episode showing her to cause deliberate damage to the class's project. Lampshaded by Arnold, though he's crushed that his cousin would do such a thing.
- What You Are in the Dark: Janet fails this big-time. When she comes to the classroom, alone except for a "bug" (actually the bus with all the students inside), she notices the bottles with scent and the largest bottle that is obviously the class's contest entry. Realizing that the entry will win the trophy and beat her scent, Janet briefly hesitates before adding skunk smell to the large bottle and leaving with a Slasher Smile about it, teasing Carlos about how the class will be lucky to get 4.5 noses. After the class fixes the scent and wins the trophy, Carlos reveals to Janet that they know she sabotaged the smell, which causes her to blush.