When me and my sister were kids, my dad used to sing us that song by Cream called "A Mother's Lament", and if you've heard it, you know it's a rather sad song, in a funny way, about a mother who turns her back on the tub for just a second so that she could get the soap, only to turn back around and find that her baby was so tiny, he was sucked down the plug.
Needless to say, we were afraid of going down the "pluggole".
A childhood belief about bathrooms

you weren't the only one
51 of you believed this
- I used to think that if you take the plug out of the bath it will suck you into the bath— awesome kid
- i thought that when you were in the bath you would get sucked down the drain— blake
- I used to believe that if you pulled the plughole while you were in the bath, you would get sucked into it!— The Young Actor - age: 11
- When I was little, I was afraid of the bathroom drain, I thought it would suck me down the hole.Anon
- I was always very afraid of being sucked down the plug hole after I'd finished having a bath.Anon
- i used 2 believe that if i stayed in the bath long enogh i would get sucked down the plughole— dude