Thomas comes from Thomas and Friends, the long running British children's series about Thomas the Tank Engine and the other locomotives on Sodor, first broadcast in 1984 and based on books from the 1940s. Online, editors took the familiar friendly train imagery and paired it with an absurdly boosted horn for contrast humour. Short clips built around that bait and switch spread across meme pages and video edits in the 2010s and 2020s, and the sound remains popular because the setup is instantly recognisable while the blast still catches first time listeners off guard.