Airdate: August 15, 2012
Garmadon brings back an ancient beast called a Grundle to destroy the ninja and prevent them from training the Green Ninja. By doing so, he also transforms the Ninja into kids, forcing them to have to find a way to transform back as well.
This episode provides examples of:
- Bittersweet Ending: The day is saved, but Lloyd has to sacrifice his childhood, accelerating the time to the Final Battle.
- Fountain of Youth: This is inflicted on the main four Ninja, though Zane suffers a mild Logic Bomb when asked about how Nindroids age.
- Innocuously Important Episode: As stated below, this episode would be complete filler if it weren't for Lloyd's Plot-Relevant Age-Up.
- Not Now, Kiddo: When the kid Ninja try to tell the adults what has happened, no one believes them.
- Plot-Relevant Age-Up: This episode is important because it's when Lloyd is enhanced from a kid to a teenager, which he remains as for the entire rest of the series. Otherwise, it'd be straight Filler.
