There are usually only one drain in a bathtub - the one in the floor. Well, when I was little, the baths had two drains, the second one built-in above the floor one. So since it was always to dark, I used to believe there were rats living in there. Needless to say, I didn't bathe too close to it.
A childhood belief about bathrooms

others believed things like this
- When I was little, I used to believe I could fly from my bed but I didn"t ....I fell on the floor!Anon
- That there was a zombie living behind the bathtub in the upstairs bathroom.Anon
- I used to believe that I would be paralysed if I sat on the floor for more than 20 minutes— bittergrass
- That if you hit the floor from a really big hieght in you dreams you die— Danielle
- I used to believe that the people that worked in stores slept right there on the floor and lived there. Anon
- I was told that if you dropped food on the floor, the devil kissed it. — Teresa