I had a fear, that if any arms or legs dangled off the side of the bed, something sinister from underneath would reach up and grab it. While that obviously is not true, I'm still funny about letting limbs dangle off the side of the bed.
To the tornado comment above--each time there was a tornado watch (which I often confused with a warning), I would go to my room and collect my baby dolls, My Kirsten American Girl doll and all of her stuff, and bring them to the basement (barbies were already in the basement) so they would not get blown away.
Drove my mother NUTS!