The MSE-6, better known as the mouse droid, first appeared in Star Wars in 1977, scurrying through the corridors of the Death Star while larger events unfolded around it. Small, boxy and single-minded, it became a favourite background detail for fans because it felt alive despite having no dialogue. The droid has since returned across later Star Wars films, series and games, and its distinctive squeaks and rolling whir are now used online as shorthand for a harmless little machine minding its own business.