When I stayed over at my grandparents' house and they gave me a bath, they said that if you stayed too long in the bath you would become scrunched and small like a raisin and fall down the drain. It seemed reasonable because if you stay in water too long, your fingers do start to look raisin-like.
A childhood belief about bathrooms

others believed things like this
- I used to believe if you stayed in water too long your skin would get really wrinkled and stay that way.Anon
- i used to believe that when you sat in the bath to long and got pruny
that the water made you old— Jami - When I was little I thought that if I stayed a long time in the water I would become a mermaid.— Salma
- I used to believe that if you soaked a raisin (or prune) in water, it would turn back into a grape (or plum).— C.C.
- how many us believed you would go down the drain with the bath water? I did!— Amy
- I used to think the woman on the the Sunmaid Raisin box was my mom— Me