This sound is associated with South Park's episode "The Brown Noise," first aired in 2004, which popularized the show's joke about the mythical brown note. Online, the clip spread beyond fans of the series and became a reusable meme sound for poop jokes, prank edits and absurd low-frequency reveals. It still shows up because the premise is instantly recognizable, easy to set up in a short video, and fits the same kind of crude humor as fart with reverb.
About this sound
A short Brown Note style sound from South Park, used in memes and edits when a scene needs a gross, low rumble punchline.
This clip is the South Park Brown Note sound, a brief low, droning tone associated with the show's joke about a frequency that makes people lose control of their bowels. It sounds like an ominous bass-heavy hum rather than a melody or spoken line. The effect is uncomfortable, ridiculous and instantly sets up a gross-out gag, which is why people use it in meme edits, prank audios and sudden comedic reveals where a serious moment needs to collapse into pure nonsense.