This clip is associated with Jimmy Neutron, the Nickelodeon cartoon character from The Adventures of Jimmy Neutron, Boy Genius. Online, the short “later ni” section became useful as a reaction sound because the cutoff itself is the joke. It spreads mainly through meme edits, reposts, and short-form videos where creators use recognizable cartoon audio for quick punchlines. Its appeal lasts because it is short, clean, and flexible enough to work as an exit line, awkward transition, or intentionally incomplete sign-off.