Write a Novel: The Graduate Student

Write a story about a 27 year old graduate student shrunk by his 18 year old underclassmen roommate. The graduate student is living on campus in undergraduate housing which is why he is the roommate of an undergraduate. This is because graduate student can’t afford to live on his own. He’s a teaching assistant or something. Both straight guys. I imagine it starting off as an accident and eventually over time lead to entrapment and other humiliations. Looking to discuss this concept before writing begins. Suspense, horror, mature (adult) themed.