The exact origin of this short curd clip is not documented, and it is best understood as a small piece of online meme audio rather than a line from a known film or show. Short, single-word voice clips like this spread because they are easy to reuse, easy to recognise, and easy to drop into almost any conversation or edit. The word itself is ordinary, which is part of the joke, and creators use it as a deadpan reaction when a moment feels strange, random, or anticlimactic. Its popularity comes from that simplicity and from how listeners understand the gag.