Louis Tully is a fictional character from the 1984 film Ghostbusters, portrayed by actor Rick Moranis. He is depicted as a quirky and somewhat awkward accountant who becomes involved with the Ghostbusters after experiencing supernatural events in his apartment. Louis is known for his comedic personality and his enthusiastic, yet clumsy, attempts to fit in with the Ghostbusters team. In the film, Louis is also the neighbor of Dana Barrett, played by Sigourney Weaver. His character adds humor to the story, especially when he transforms into the keymaster, a pivotal role in the plot involving ancient spirits. Louis Tully's charm and comedic timing have made him a memorable character in the Ghostbusters franchise.