What precisely makes rocks move around on their own leaving obvious tracks in the sand?  Even more important, there are no other tracks around them and no one has ever seen them move — yet they are moving and leaving notable trails in their wake.  “The exact mechanism of their movement is not known…”

Need proof?  Go look at today’s Earth Science Picture of the Day for an example.  Be sure to check out the larger version of the photo for the best view of this interesting, if not bizarre, phenomenon.