The Floorwalker

The Floorwalker is a 1916 American silent comedy film, Charlie Chaplins first Mutual Film Corporation film. The film stars Chaplin, in his traditional Tramp persona, as a customer who creates chaos in a department store and becomes inadvertently entangled in the nefarious scheme of the store manager, played by Eric Campbell, and the stores floorwalker, played by Lloyd Bacon, to embezzle money from the establishment.

Roughly seven minutes from the start of the film, Chaplin and the stores floorwalker, Lloyd Bacon, stumble into opposite doors of an office and are intrigued by their likeness to each other. They mirror each others movements to deft comic effect in a way that is believed to have inspired the mirror scene in Max Linders Seven Years Bad Luck 1921. In that comedy film, Maxs servants accidentally break a mirror and try to hide their mistake by having one of them dress just like their employer. Then, when Max looks into the nonexistent glass, the disguised servant mimics his every action.Max Linders movie in turn inspired many similar scenes, most famously in the Marx Brothers film Duck Soup. Later renditions can be found in the Bugs Bunny cartoon Hare Tonic, the Mickey Mouse cartoon Lonesome Ghosts, and in the TV series Family Guy and The XFiles. A scene in The Pink Panther, with David Niven and Robert Wagner wearing identical gorilla costumes, mimics the mirror scene. Harpo Marx did a reprise of this scene, dressed in his usual costume, with Lucille Ball also donning the fright wig and trench coat, in an episode of I Love Lucy. Additionally, an early episode of The Patty Duke Show contains a mirror scene in which the characters Patty and Cathy Lane both played by Patty Duke act out a version similar to the one found in the film Duck Soup. ........

Source: Wikipedia