Calypso is one of Apple's built-in message alert tones for iPhone, and it became widely familiar during the iPhone X era, when many users kept the default sounds for texts and notifications. Its light, percussive melody stood out from harsher ringtones, which helped it become a shorthand online for a phone receiving a message. Editors and meme makers now reuse the short clip to fake a notification, punctuate a reveal, or add a familiar phone sound without recording a real device.