Line launched in Japan in 2011 as a messaging app and grew popular across Asia for its free calls, stickers and bright notification sounds. Its incoming call chime became familiar from everyday phones long before it circulated as a standalone clip on soundboards. Creators now reuse it alongside a discord call sound for scenes about online contact, group chats and missed connections. Because most viewers know the melody from the app itself, a brief play is enough to suggest a call is waiting, which keeps the joke or transition easy to follow.