This Explains A lot:

When I was little my favorite story was about a woman that always wore a scarf around her neck. She got married and told her husband to never remove it and they lived years without him ever seeing her neck. Then one night she was sleeping ad he couldn't take it anymore and he untied the scarf and removed it and then .....

HER F*CKING HEAD ROLLED OFF!

I loved this story (and the illustrations) and never stopped to think it was odd or gross. I just thought that pesky thing curiosity was a jerk, I mean he killed cats and made your friends heads fall off.

Any way, the point of this post is for someone to tell me the name of the book. I would hate to think I made this story up when I was 5, that could mean a lot more about the psyche) Maybe Nikki can help me, she remembers V and square pegs so maybe she knows this book too.