This sound comes from Filthy Frank, the internet comedy character created by George Miller, whose YouTube videos became widely shared in the 2010s. Short reaction lines from that era spread across meme compilations, reuploads and soundboards because they were easy to drop into fast edits. "This is cancer" stuck around as a blunt reaction for cringe, chaos and intentionally uncomfortable humor. It is still used in meme culture for the same reason as a shocked sound: it delivers instant disapproval in barely over a second.