The tommy gun is the nickname for the Thompson submachine gun, developed in the United States around the end of the First World War. It became closely linked to Prohibition era gangsters, police and soldiers, and later fixed in popular culture by gangster films and war movies. Its distinctive rapid, rattling fire made it easy to recognise even without visuals. Online, clips of that fire are reused as a stock effect for edits, games and parodies, where the historical reference instantly signals old school automatic gunfire and exaggerated action.