Monday Mystery

As you might recall, I was at the beach last week with my sisters. Well, I noticed this:

See this placemat? Well, I had two of them. 

If you blow up this photo and look at the dining table, you can see that I was using the two of them as a sort of table runner under the candles. One is gone. I searched everywhere. I cannot imagine what happened to it. 

It's not a big deal. I only paid a buck for it--found on clearance at Bed Bath and Beyond. But still, a mystery.