Of Unknown Origin is a 1983 Canadian-American horror film directed by George P. Cosmatos and starring Peter Weller. It was written by Brian Taggert and based on the novel The Visitor by Chauncey G. Parker III. It was filmed on location in Montreal, Quebec but set in New York City. The film won two awards at the Paris Film Festival.
Mild-mannered everyman Bart Hughes has a great bourgeois life in New York City. When his wife and child leave for a vacation, Bart stays behind to work on a project that should get him a promotion. Some sort of rodent in his basement starts to bother him and consumes his time. Bart becomes obsessed with it and eventually starts losing his mind while trying to kill the creature, destroying most of his house in the process.
Vincent Canby of The New York Times had nothing but disdain for the movie, but lightly praised Weller's performance and opens his review: