Phineas, Ferb and the gang build a giant replica of the Gordian Knot and Candace thinks her day will be easy when the boys actually ask her to get Mom if they cannot get out, but her plans are derailed when Jeremy asks her to open his personal mini safe. Meanwhile, Doofenshmirtz plots to eliminate all buffet foods with his Eat-it-all-inator.
Tropes:
- Artistic License – History: Alexander the Great (as portrayed by Buford) is seen cutting the Gordian Knot with his right hand. However, Alexander the Great was left-handed.
- Big Eater/Buffet Buffoonery: Dr. Doofenshmirtz invents a device that allows one to consume massive amounts of food without gaining weight, in order to put all-you-can-eat buffets out of business.
- Brick Joke: When Jeremy brings the safe over to Candace, he mentions that he still has all of his baby teeth. At the end of the episode, they fall out.Candace: Eww... I mean, cute!
- Cut Lex Luthor a Check: One of the customers at the first buffet suggests Dr. Doofenshmirtz could sell his Eat-It-All-Inator as a dieting tool, but Doofenshmirtz rejects it in favor of his current Zany Scheme.
- Cutting the Knot: The Big Idea is inspired by the Trope Namer, the mythical Gordian knot that was impossible to untie (but was easily cut open by Alexander the Great with a sword). The gang attempt to subvert it by actually untying the knot instead of cutting it, but the plan fails when Candace eats the knot. Played straight when Buford uses his head to open the safe at the end.
- Distant Duet: The "Un-Untie-able Knot" number shifts back and forth between the kids trying to untangle the giant Gordian Knot, and Candace and Stacy trying to find out what's in Jeremy's safe.
- Eat the Evidence: Candace gets hit by Doof's -inator, making her feel incredibly famished... and the boys' Big Idea just so happens to have been made from licorice.
- Foreign Queasine: With foods like "entrail waterzooi" and the "Mystery Lump", Dr. Doofenshmirtz admits that Drusselstenian food is terrible.
- Freudian Slip: As Candace is eating the licorice knot:Buford: I am so in love with her right now.
Baljeet: What?
Buford: Nothing. - Gratuitous Spanish: After Buford crunches the safe with his head, he offers it to Candace saying, "¡Para used, señorita!" ("For you, missy!")
- In Medias Res: The episode begins with the plan of the day already pre-decided and the licorice sitting in the backyard. This is lampshaded by Buford.
- Noodle Incident: Candace warns Phineas not to bring up the "clothesline incident" when he tries to explain why their mom is their back-up plan if their attempts to untie the Gordian Knot goes wrong.
- Record Needle Scratch: When Candace interrupts Phineas before he can finish telling the gang about the clothesline incident.
- Shout-Out:
- The Big Idea, of course, is inspired by the Gordian Knot faced by Alexander the Great.
- The slogan for Doofenshmirtz's Drusselstinian-style buffet is "Doof spelled backwards is 'food'", a reference to Serutan, a laxative made from the 1930s to the 1960s, whose slogan was "Read It Backwards", because "Serutan" spelled backwards was "Natures".
- When Buford somehow manages to get himself in a knot, Buford says, "I'm a victim of circumstance!"
- Use Your Head: At the end of the episode, Buford smacks the safe against his head and finally manages to open it.
- Who's on First?: Done by Phineas and Buford in the intro, though they riff on the homophones "knot" and "not".
