The phrase 'Qui tu chuis?' is informal French slang for 'Who are you?', widely used online as a joking challenge when someone acts out of place. The short clip has circulated as a reaction sound on meme pages and in gaming edits, where its blunt, questioning tone fits moments of surprise and disbelief. Like other confused reactions such as Huh? Ceeday, it works because the line needs no translation to feel confrontational, even for listeners who do not speak French. Its brevity makes it easy to drop into edits, duets, and short-form videos.