when I was in year 4 (age 7-8 for those of you not familiar with the british school system), some kid told me that if you went into the toilets, turned the lights off and said something like "I believe in St. Mary's Lighthouse" three times, a ghost would come out.
Of course, I believed him - I went in, turned the lights off and damn near shit myself, only managing a half-arsed "hello?" before I ran out of there.
A childhood belief about fear of

others believed things like this
- I used to believe that there where little mice the the street lights that turned them on and off.Anon
- I believed that traffic lights had police officers inside them, turning the lights on and off...— CrowHeart
- when i was about 5-8 i used to believe that oompa loompas lived in traffic lights and controlled the lights!!— ~wierd ~
- I thought the Holy Ghost was the ghost of the Virgin Mary.— Texas granny
- For a very long time I believed that there were little men underground that changed the traffic lights!— Melissa
- I used to believe that school was a place kids go to get turned into adults.— Samantha