Ms. Frizzle's class has to come up with a mascot for its soccer team. Phoebe wants it to be a butterfly, but everyone else thinks that's a dumb idea...they're too wimpy! That's when know-it-all Janet suggests a bog beast mascot. The kids think it sounds really cool. But just what is a bog beast? Find out when you join the class on an exciting field trip to a real live bog, where they learn all about bog beasts and butterflies!