Alligator is a 1980 American independent horror film directed by Lewis Teague and written by John Sayles. It stars Robert Forster, Robin Riker and Michael V. Gazzo. It also includes an appearance by actress Sue Lyon in her last screen role. Set in Chicago, the film follows a police officer and a reptile expert who track an enormous, ravenous man-eating alligator flushed down the toilet years earlier, that is attacking residents after escaping from the city's sewers.

Robert Wallace Foster Jr., known professionally as Robert Forster, was an American actor, known for his roles as John Cassellis in Medium Cool (1969), Captain Dan Holland in The Black Hole (1979), Abdul Rafai in The Delta Force (1986), and Max Cherry in Jackie Brown (1997), for which he was nominated for the Academy Award for Best Supporting Actor.