The phrase ne znaet is ordinary Russian for he does not know or she does not know depending on context, and as a standalone clip it circulates online as a compact reaction sound rather than a song or scene quote with a confirmed source. Short foreign language phrases like this spread through soundboards and short video edits because the meaning is carried by tone and timing as much as translation. It remains in use for clueless characters, failed answers and deliberate shrugs where a longer explanation would slow the joke down.