The line comes from Tobias and the Half-Pariah, a Thomas the Tank Engine fan film created by Tines Sensahthe. Set on the Island of Sodor, the story follows the engine Tobias and features familiar engines including Thomas, Percy, Gordon and Henry in a much darker adventure than the television series. Clips from the film later circulated in Thomas edit communities and meme pages, where dramatic lines were lifted out of context for jokes, and this angry island warning became a reusable reaction sound.