The exact origin of this specific short "la la la" meme clip is unclear from the available details, but it fits a common style of ultra-short vocal sounds reused in meme edits and reaction posts online. Clips like this spread because they are easy to loop, easy to recognize and simple to drop over awkward, smug or unserious moments. Its staying power comes from how quickly it changes the tone of a scene, much like a bruh reaction or a buzzer style punchline.