The Magic School Bus Butterfly and the Bog Beast
The class while preparing for a soccer game finds themselves without a mascot, and they reject Phoebe's choice of butterflies in favor of Janet suggesting a "bog beast". No one knows what a bog beast is, however, so Ms. Frizzle takes the bus to a bog to find out. While there, Janet decides to hunt down a butterfly to feed to a bog beast and the class gets shrunken.
- Action Survivor: Butterflies are this in a world where everything is trying to eat them.
- Blind Without 'Em: Janet loses her glasses when she finally catches the bus in butterfly form. It's part of the reason why the butterfly Jump Scare causes her to scream and fall down.
- Bread, Eggs, Breaded Eggs: After the class and Janet learns that a bog beast is just a butterfly, they decide to make the school mascot "The Bog Beast Butterflies".
- Call-Back: Ms. Frizzle commentates on the soccer game the way she did in "Plays Ball".
- Chekhov's Gun: Phoebe redecorates the bus's wings in butterfly form to create fake eyes and scare Janet.
- Crying Wolf: Ralphie as a Running Gag repeatedly mistakes various caterpillars and butterflies as "bog beasts". By the end of it, even Wanda is mimicking his cries in a deadpan tone before getting scared herself.
- Defeat Means Friendship: One of the few times Janet does this when she learns that a bog beast is just a butterfly, and even dresses up as a "Bog Beast Butterfly Mascot".
- Determinator: Despite getting shrunken, Phoebe chases after Janet to Shoo the Dog with the butterflies. Likewise she stands her ground about making butterflies the school mascot.
- Easily Forgiven: Considering how mean Janet was in this episode to her, Phoebe was quite kind to her in the end.
- Heart Is an Awesome Power: As the class learns, caterpillars and butterflies have extraordinary means of defense that are nonlethal but effective: camouflage, imitation of other animals, and Jump Scare.
- Idiot Ball: The class and Ms. Frizzle turning the bus into a butterfly while Janet is in hunting mode.
- There's also the fact that the class believes Janet's claims that Phoebe is trying to sabotage them because they're playing her old school in their upcoming match, with no evidence other than Janet's own words.
- Jump Scare: A butterfly can pull this off with extreme coloration on its wings. Ralphie gets scared at least twice.
- Kick the Dog: Janet wants to catch a butterfly to feed it to a bog beast, and she keeps insinuating that Phoebe wants the opposing team, her "old school," to win. Fortunately she never gets the chance, since a bog beast is a butterfly.
- Know-Nothing Know-It-All: Janet. She suggests "the bog beast" mascot, but when Arnold and Ms. Frizzle question her, she admits that she doesn't know and that a friend told her.
- Manipulative Bastard: Janet easily gets everyone to turn on Phoebe.
- Nice Job Breaking It, Hero!: The class barely evades Janet when the bus turns into a green camouflaged butterfly. Then Arnold in testing the de-shrinker activates the "do-dinger" right after Tim warns him; the sound allows Janet and Liz to find them.
- Pick on Someone Your Own Size: Phoebe calls after Janet to do this.
- Running Gag: The "do-dinger" that dings every time Arnold tries the "de-shrinker".
- Seldom-Seen Species: A zebra butterfly appears.
- Shoo the Dog: Phoebe tries to chase away the butterflies before Janet can catch them, but it turns out the butterflies can protect themselves.
- Took a Level in Jerkass: Liz, who goes along with Janet's antics in this episode since insects are her Trademark Favorite Food.
- What Kind of Lame Power Is Heart, Anyway?: The class asks this when Phoebe suggests that they make the mascot the butterfly, since as far as they know, butterflies are only "pretty".