My 6-year-old sister is convinced that there's a frog in our sink overflow. (This isn't strictly a Used To Believe.) It's a girl frog called Charlie. I think my sis believes this because of the gurgling noise the sink makes when you pour water down the overflow. It doesn't even really sound like croaking...
A childhood belief about imaginary friends

others believed things like this
- My aunt always used to tell me that if I swallowed gum, I'd turn into a frog!— Deana, Las Vegas, NV.
- I used to believe that if you kiss a frog then the would would really turn into a king.— jing
- I used to believe that tapioca was frog/fish eyes.— Dana
- When I was younger, I used to believe toads were male and frog were females.— Claude-Eugène
- I used to think that hiccups were caused by a frog in my chest who would jump and croak.— Elizabeth
- My father told me tapioca was frog eggs in pudding. I still can't eat it!Anon