I had (and kind of still do) an imaginary twin brother named 23.
(Yes. His name was really 23.)
We always fought over simple, small issues, and he took the pleasure of picking on me while I was in classes, knowing I couldn't do much about it then.
Almost every day, I'd shoot glares at him, but the boy sitting across from me would think I was glaring at him instead.
...
23 was mean....
A childhood belief about imaginary friends

others believed things like this
- I used to have an imaginary friend named Mr. Nobody. He would protect me from my imaginary enemy, Bad Elmer.— Kdees
- when i was growing up i had two imaginary friends. One was named Jennifer, the other was named Onion.— Tessica
- I used to think people were made of dirt and mayonnaise. I kind of rememeber picking this up at church.— julia
- I used to believe that every person in the world had a twin, and that I had a long-lost twin in France.— Ashley
- I used to wonder what kind of insect "uncles" were named after.
I had "Ants" figured out.— Kimberly in AZ - i used to think a small man named homer lived in my grandmother's freezer and made ice. — ana