Myself, my brother and all of our friends were under the impression that a monster dubbed "Mothman" for his giant-mothlike appearance and ability to fly - lived in our basement.
A childhood belief about basements

others believed things like this
- I used to believe a spider monster was in my basement— Kelly bulanek
- i used to believe that a ghost lived under my bed and that a giant lived under our dining room table.— nameless
- when i was little i used to believe that darth vador lived in my basement, and i was scared to go down there.— Jilli
- My sister told me that Fraggles lived in our basement. I used to sit down there forever so I could see them. — Suzie
- My grandma told me and my sisters that the boogie man lived in her basement and if we cried he would get us.— Paulette
- I Used To Believe That GayNess Came From Lack Of Confidence In Ones Appearance— Mr Payne