Keks is the everyday German noun for a cookie or biscuit, and this recording circulates online simply as a short isolated pronunciation of that word in German. No specific film, show or creator is confidently linked to this version, so its popularity comes from how it is reused rather than a famous scene. German words dropped into English language edits have long been a staple of absurdist humour, and a brief, clean clip like this is easy to trim, loop and share as a soundboard staple.