|Season 3, Episode 30|
|Airdate:||Jul 09, 2004|
|Writer(s):|| Mo Willems|
|Storyboards by:|| Guy Moore|
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Figure Out Unusual Nerd's Tantalizing And Impossible Necessity
Summary: One of the girls' bathrooms at Gallagher Elementary hides a secret: a fountain of eternal youth. The DCFDTL have taken the interest of destroying it. Now Numbuh 1 and his team must save Leaky Leona and stop the Delightful Children from destroying the fountain.
- Villains : DCFDTL
- Ally: Leaky Leona
- Cameos: Lunk (delightfulized)
- Locations: Gallagher Elementary School, Ancient School
- Villain Technology:
- Really Really Incredibly Destructive Machine
- Fountain Water Squirt Gun
- When Sector V was changing back to their older forms, it is clear that Nigel's hair color was brown.
- This episode explains why Abigail hates the DCFDTL. She lashes out in anger a couple of times, and there's an explanation to why she refuses to be leader of Sector V.
- Kuki was the closest to being destroyed by Leona, as she was shot with the water cannon three times versus everyone else, who were shot up to only twice.
- During the first scene in the girls' bathroom, the stripe on Lenny's football helmet is red instead of white.
- This is the second time Lenny's face is shown.
- At the beginning of the episode, when Sector V are all in the girls bathroom, Numbuh 2 finally told a decent joke to Numbuh 4 about Leaky Leona.
It is revealed in this episode that the Delightful Children were responsible for Nigel Uno's permanent baldness
The statue of the Librarian in the ancient Library bears a striking resemblance to Madam Margaret (in her robotic form).
- This episode bears a slight similarity to Harry Potter and the Chamber of Secrets, in that there is a series of chambers buried beneath the school only accessible through a girl's locker room.
- Despite the Delightful Children once being Sector Z they stayed the same even though they became younger then they had been when they were transformed.
- This episode is based on the story of the Fountain of Youth, turning it into a water fountain. It also presents the subterranean "other school" into a parody of an ancient temple, with several of the main parts of the school system - i.e. library, lunchroom, and gym - being used as models for the various chambers that heroes have to pass through in archaeology-based movies that are designed to test their worthiness.