The line comes from Gran Torino, the 2008 film directed by and starring Clint Eastwood as Walt Kowalski, a gruff Korean War veteran who fiercely protects his Detroit home and neighbourhood. Early in the film he confronts a young man on his lawn with the curt warning, and the moment quickly became one of the movie's most quoted scenes. Clips of the line later spread across YouTube, soundboards and social media, where creators reuse it as a shorthand for territorial grumpiness, unwelcome visitors and old-fashioned tough-guy humour.