When I was very young, I went on a vacation with my parents. There was a button in the hotel room, apparently to request room service.
My parents, in an attempt to prevent me from pressing the button, told me that it was a "Goblin Button"- and that if you should press it, the goblins will come.
To this day, I can remember staying awake throughout night, still as can be, just staring at the button! I was scared to death, truly believing that the goblins would storm the place, just with the touch of the button (which happened to be next to the bed! Ugh!). I was afraid of somehow rolling over in my sleep and accidentally pressing it.
A childhood belief about monsters

others believed things like this
- I used to believe that inside each volcano there was a guy who'd press a button to make it erupt.— Jim, UK
- I used to think that babies were made when you press your mums belly button.
Then a baby would fall out— Chris Hyndman - I used to believe your belly button was a knot that held you together - my parents had wierd anatomical views— anne
- I used to believe that If I stuck my finger really far inside of my belly button I could touch my insides.Anon
- That the belly button was the place where babies where born from.Anon
- when i was young i was told that if i played with or turned my belly button that my bum would fall off — lee hull