When I was about 6, I was absolutely terrified of The Things That Go Bump In the Night, which were (in my mind) an entire race of monsters and boogiemen and ghosts and demons and the like. So I deliberately made up an imaginary friend named Midoon (MIDnight-nOON) who would protect me from the dark monsters. He was the actual, real Prince of the Night, but the Things had stolen it from him and he had to defeat them all to get it back.
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
- I used to believe that hazelnuts were real currency, with actual value to buy things. — Valerie, Ottawa Canada
- I use to cover my head at night because I thought monsters would give me a bad hair cut while I was sleeping!— Amy
- When I was about 6 or 7, I had an imaginary friend, who left for ice-cream one night. He never returned.— His name was Jimmy
- I used to believe that my stuffed animals would come alive at night to protect me.— Julie
- I used to believe that towels were sleeping ghosts, and at night they would come out and get you— bajd