What is this?

First, I apologize, this is my third post in a row that is not technical. I promise I will get back to the real purpose of this blog in my next post.

Now, on to the question. Does anyone recognize this device? I found it in my closet the other morning. I suspect I probably took it out of a bag after a trip, or picked it up instead of stepping on it in one of my kids' rooms. I probably knew what it was at the time, probably thought I would stick it there for a few days and deal with it later. Now it is later, though, and I have no idea what it is or where it came from.

It takes 3 AAA batteries. It has no identifying markings of any kind. Inside the battery compartment there is no writing. When I turn it on it makes a very high pitched, very low volume whining noise. There is nothing on the sides that are not shown in the two images above. You now know as much as I do about this thing.

If you know what this is, really know what it is, please post a comment. Thanks.

Update: We have a winner! I won't publish the answer here, in case you want to guess. Check out the comments for the answer.