There were spiders under the water in the bath, and if you didn't get out before the water drained away well ... they'd be all wriggly (and stuff).
A childhood belief about bathrooms

others believed things like this
- I used to believe that if i splashed water on the wall during a bath, the water would turn into spiders— justin
- I used to believe that water towers were giant metal spiders. Don't ask. — Goatgirl
- I didn't think you could put out a fire with hot water - only cold water would do.— Katti Pytt
- how many us believed you would go down the drain with the bath water? I did!— Amy
- When I was a kid, I use to believe, when I put salt in my bath water I will turn into a mermaid.— marletha
- i used to believe that when you sat in the bath to long and got pruny
that the water made you old— Jami