This short line comes from DELTARUNE Chapter 5, where Flowery delivers it as a brief voice clip that fans quickly lifted out of the game. Short character lines like this travel well because they are easy to recognise, easy to place over other footage, and instantly signal confusion or disbelief without needing the original scene. As clips from the chapter circulated in edits, reaction videos and streams, the phrase became a handy shorthand for asking someone to repeat something unbelievable. Its appeal has lasted because the delivery is memorable and the wording fits so many everyday moments.