With no confirmed original source, this clip has spread purely as a short form reaction sound on soundboards and in edited videos. The phrase think it's fake sums up a very online kind of skepticism, the instant doubt that follows viral tricks, filtered photos and too neat coincidences. Because the line is short and instantly understood out of context, it gets reused as a punchline, a comment in audio form, and a way to invite viewers to question what they just watched.