Everyone knows dormitories abound in ghosts, spirits, etc. I've resided in 2 dorms (high school and college).
I'll start with high school. There was a time when the entire dorm really felt haunted. Open doors from all the rooms in one floor would close either all at once, or one at a time. When in one end of the hallway, you'd see shadowy figures at the other end. My roommate and I named them dementors lol. In my room, if the door was open, me/my roommate would just say "please close the door" and the door would shut on its own even without wind.
And then other more outright creepy stuff: one time, a loud scream was heard throughout the dorm. The most religious girl we knew was shaking and crying, saying she saw a white lady. One time, I caught a friend of mine walking out of the bathroom, her face pale. She said while on the corridor, she saw one of the upperclassmen leaving the bathroom. When she got inside, she saw the same upperclassman. Two friends of mine saw a baby running down the corridor, all black and smoky. In my friends' room, the guitar would strum on its own, and there would always be this heavy wind that's not anywhere else. My friend said while she was sleeping over at my room, she saw a smoky figure under my bed. Even our dorm manager says that in her room, she would sometimes be awakened by little hands poking her and laughter, like there's a group of little girls playing.
Long story short, our dorm had to be cleansed by a priest with holy water.