Miss Webb tells Fitz to eat ketchup instead of mustard because it's healthier. That is incorrect; mustard has less sugar, sodium, and carbohydrates, making it healthier than ketchup.
Brian: (to Carl) So you're back, huh?
Carl: Yeah. You got a problem with that?
Lexi: Welcome back!
Fitz: (innocently) New hair net?
Brian: You got any mustard?
Ms. Webb: Mustard?!! Don't ever use that word in my presence!
Arnie: Do you know what happens to a cocoon when the bug comes out? It shrivels up and dies. And sometimes... it even eats it.
Ms. Dewberry: It is metamorphosis that defies all laws of physics in nature.
Brian: (to Fitz) If you ask me, her hair defies all laws of physics in nature.
Principal Pussman: (over intercom) I expect all of you to buy lunch from now on. (to himself) Welcome... to my nightmare. (laughs evilly)
Sarah: (concerning her lunch) Smells like feet.
Brian: (to Carl) Where's the last place you cooked? A penitentary?!
Lexi: (concerning the food) Oh, look, toxic waste!
Fitz: So that's what they do with it. I think I'll stick with my trusty bologna.
The title joke says that this episode is filmed in "Insect-O-Scope."
It is book #3 in the series.
This episode was released on a VHS tape titled Back to School.