Today’s Wonder of the Day was inspired by madelyn from crown point, IN. madelyn Wonders, “Why can you not touch an elf on the shelf?” Thanks for WONDERing with us, madelyn!

Do you ever get that eerie feeling that someone is watching you? You're walking along, minding your own business, and then the hairs on the back of your neck suddenly stand up.

You're sure a set of eyes are on you. You look around, but there's no one there. Still, you can't seem to shake that feeling of being watched.

For many kids, that feeling might occur more frequently as Christmas approaches. And it might happen in their bedroom, in the bathroom, in the kitchen, and in the family room. In fact, it might happen just about anywhere around the house.

If they look carefully, though, they'll spot those eyes that are keeping tabs on them. They belong to a tiny creature clad in red. What are we talking about? It's an elf…and it's probably sitting on a shelf!

The elf on the shelf phenomenon that has become wildly-popular over the past several years is based upon a book called The Elf on the Shelf: A Christmas Tradition. Published in 2004, it's a children's picture book written by Carol Aebersold and her daughter, Chanda Bell. The book was illustrated by Coë Steinwart.

The book comes with a small toy: an elf figure that acts as a scout sent by Santa Claus from the North Pole to help determine whether kids are naughty or nice. According to the story, when a family adopts an elf and gives it a name, the elf receives its special Christmas magic.

Each night, the elf flies to the North Pole to report back to Santa about the events of the day. Before morning, the elf returns to its family's home and hides in a new spot to watch over the children throughout the day. When they awaken, kids scour the house, excitedly looking for their elf. It's like playing a daily game of hide and seek!

After Christmas, the elf returns to the North Pole, where it stays with Santa Claus until the next holiday season rolls around. According to the book, there is only one rule: don't touch the elf. If the elf is touched, it might lose its magic. Kids are free to talk to their elves, though, with the hope that the elf will convey their Christmas wishes directly to Santa.

The elf on the shelf phenomenon has grown steadily over time. The book has sold more than eight million copies and won many awards. An animated television show based upon the book debuted in 2011. The following year an elf on the shelf balloon made its first appearance in the Macy's Thanksgiving Day Parade.

It's easy to see why these scout elves are popular with kids. However, it has surprised many people to see how much fun parents have with them, too. The elves are sometimes placed creatively in miniature, humorous scenes which delight children and their families. Families sharing these scenes on social media has sparked websites to create photo galleries of the elves in funny poses.

Wonder What's Next?

Tomorrow’s Wonder of the Day is really tall and full of water. What could it be?