The Earth is invaded by stingray-shaped alien "slugs" that ride on people's backs and control their minds.
The Puppet Masters is a 1994 science fiction film, adapted by Ted Elliott, Terry Rossio and David S. Goyer from Robert A. Heinlein's 1951 novel of the same title, in which a trio of American government agents attempts to thwart a covert invasion of Earth by mind-controlling alien parasites. The film was directed by Stuart Orme and stars Donald Sutherland, Eric Thal, Keith David, Julie Warner and Andrew Robinson.