When I was small I used to imagine that when I was lying awake in bed at night the Power Rangers would saw a hole in my ceiling, and I knew that one day they'd lift me up through it and I'd be able to go on an adventure with them.
This never happened unfortunately.
As well as this I imagined a little mouse family lived inside my mattress, so when up until very recently (I'm now 15) when you lie on your side and can ocasionally hear your pulse, I thought vaguely "Oh, there goes the mouse family."
A childhood belief about imaginary friends

others believed things like this
- I used to think that when I moved the mouse around on the mouse pad, I was giving the computer a massage.Anon
- I used to believe that God was Zordon from the power rangers.... heh— Dawnie
- When i was about 5 - 8 i though the Power Rangers Existed!!
Got DissapointedAnon - When I was little and had an ear infection I used to tell my parents I had a mouse in my ear.— Alison
- I used to believe a mouse lemur was a type of a rodent.Anon
- As a child I used to think that the toothy mouse existed.— Jordi Comendador