The phrase 'stop the cap' comes from hip-hop slang where 'cap' means a lie, popularised in Atlanta rap culture and the song 'No Cap' by Future and Young Thug in 2017. By 2020 the phrase had exploded across TikTok, Twitch and YouTube as a go-to callout for fake stories and over-the-top boasts. Clips of the phrase followed by laughter became a staple reaction sound in meme compilations and streamer content, usually dropped when someone gets caught stretching the truth. Its staying power comes from how naturally it fits everyday roasts and reaction videos.