Of Unknown Origin is a horror/thriller film from 1983. It was directed by George P. Cosmatosnote and stars Peter Weller, Jennifer Dale and Shannon Tweed. It is based on the novel The Visitor by Chauncey G. Parker III.
When Bart Hughes' wife and son leave their house for two weeks, he thinks it will be the perfect time for him to focus on a project that'll be sure get him a promotion at work. He's in for a nasty surprise, as a huge rat scuttles into his domain and wants to make the place its own.
These tropes are of known origin:
- Agony of the Feet: When the rat attacks Bart in the basement, it bites his foot first.
- Animal Nemesis: Bart starts obsessing over the rat so much that he refuses to leave the house.
- Batter Up!: As the conflict between Bart and the rat intensifies, he picks up a baseball bat to keep himself safe. Later, he jams some nails and rat trap parts on it.
- Camping a Crapper: The rat gives Bart a scare when Bart tries to go relieve himself in the middle of the night and finds it inside his toilet bowl.
- It Can Think: This rat seems to know exactly what to do to tick Bart off.
- Mama Bear: The rat attacks Bart when he finds its litter in his basement. And then he drops them in the sewer.
- Nightmare Dreams: Bart has a nightmare of the rat attacking his wife when he's sleeping in the bathtub.
- Pretty in Mink: Meg wears a blue fox coat in her scenes. As she and their son are away most of the movie, her fur is hence one of the luxuries not destroyed by the end.
- Pyrrhic Victory: Bart wins in the end, but his apartment is in pretty bad shape.
- With every thing else destroyed in the apartment, Bart finds one unbroken vase, standing on a bookshelf. With a "Oh, what the hell" expression on his face, he tips it over to smash on the floor.
- Rain of Blood: Bart discovers his recently adopted cat's corpse on top of his fridge when he tries to have a glass of milk and its blood starts dripping on it.
- Road Runner vs. Coyote: A rare dramatic example, as the 'Coyote' becomes increasingly unstable due to his inability to catch the 'Road Runner', which in turn is unusually vicious for this trope.
- Rodent of Unusual Size: The rat in this film is bigger than a cat.
- Shower Scene: First appearance of Meg is her having a shower.
- Title Drop: Appears during Bart's studies about rats, on a microfilm screen.
- Your Cheating Heart: Averted. When Bart's secretary, Lorrie, is visiting him, they have a close moment and he is about to kiss her...but the rat scuttles by and he hurriedly ushers her back outside.