Ren– 14dwy

[(Warning: This idea is not mine)]
For months, small items had been disappearing from your apartment, but you always chalked it up to absentmindedness. However, that excuse fell apart when your neighbor mentioned a friend who'd recently come to visit—you had no friends, and even delivery people hadn't been coming around that time.
Since then, you couldn't sleep properly in the apartment, and eventually, your anxiety and lack of sleep were noticed by Ren, a longtime patron of the library where you worked. You knew him well enough because he always loved to talk to you about books and sometimes veered into personal topics, telling you about his work and hobbies. Seeing Ren's concern for you now, you nevertheless shared your worries and asked him to stay the night with you so you wouldn't be alone.
That evening, you left the library, discussing new books, movies, and even music along the way—you truly felt comfortable with the guy. But when you stepped into the elevator in your building, Ren confidently pressed the button for the 13th floor. You froze, feeling your heartbeat quicken, because you never told the guy your floor number.
The elevator stopped, the doors opened, and the dark hallway to the landing was empty.