I had an imaginary friend who was actually my reflection. She looked just like me, of course, but her name was "Jealous" because she was imprisioned behind the mirror. I thought that if I broke the mirror she would be freed and would take her revenge, and that was why it was bad luck to break a mirror.
A childhood belief about imaginary friends

others believed things like this
- when i was young i used to believe that my image on a mirror would come to life if i broke the mirror.Anon
- I used to believe that when you cracked a mirror your reflection would come and take over your body!— XxXAbbeyXxX
- I used to believe that my reflection in the mirror was my evil twin that always had bad hair. XDAnon
- If you stare into a mirror in almost complete darkness, the devil will appear instead of your reflection.Anon
- I used to think that if a mirror with me in it breaks, I break.Anon
- I used to believe that there was a person in the mirror who looked exactly like meAnon