Dana Barrett is a fictional character from the 1984 film Ghostbusters, portrayed by actress Sigourney Weaver. She is a professional cellist living in New York City who becomes involved with the Ghostbusters after experiencing supernatural occurrences in her apartment. In the film, Dana is targeted by the ancient spirit Gozer and becomes possessed, leading to her iconic transformation into the character known as the Keymaster. Her character plays a crucial role in the plot, as the Ghostbusters work to save her and the city from the impending threat posed by Gozer.