Loose chippings
My mother told me to shut my window in the car or loose chippings ( these looked like large frogs with sharp teeth) would spring out of the hedge row and eat me. I was probably a teenager when I sussed it
A childhood belief about road signs

others believed things like this
- I thought the song "Little Deuce Coupe" was "Little Loose Tooth".Anon
- My mother told me that the tooth fairy would only come if I brushed my teeth.— Dale
- I used to believe that elfs lived in the hedge at the bottom of my garden!!
— The milky bargirl - I used to believe that the school rabbit liked the red berries that grew in the hedge. But then he died.— Charlotte
- My mother convinced all of us kids in our family that the large rhubarb in the garden was a Man-Eating Plant. — H.Miller
- I used to believe that eating burnt toast would make your teeth whiter and would brush your teeth for you.— Natasha