Happy Birthday to Me is a 1981 AmericanCanadian slasher film directed by J. Lee Thompson and starring Melissa Sue Anderson and Glenn Ford. It was released on May 15, 1981, and has since become something of a cult classic among fans of the slasher genre, with its bizarre murder methods and twisted climactic revelation.citation needed
One night en route to the tavern, Top Ten member Bernadette OHara is attacked in her car by a killer whose face cannot be seen. Unable to flee, she struggles and then plays dead to catch the killer offguard, before running to get help. She finds somebody whom she is familiar with only to have her throat slit by this person with a razor whom the audience still cannot see who is actually the killer.The Top Ten becomes concerned when Bernadette fails to show up at the Silent Woman. They soon get over it when their argument with another customer results in one of them putting a pet mouse into his beer. Mayhem ensues, and the Top Ten flees the scene. ........
Source: Wikipedia