Wondering about a strange “movement”.

I have a small area fenced in for the dogs when they want to or need to go out.  A couple of times during the day, I walk through their yard with a little hand shovel and pick up all the little packages that my loving dogs have left for me.  It is usually a simple procedure that does not take too long or too much effort, and it is well worth the time to do it a couple of times a day.  Well, yesterday on one of my dog yard policing expeditions, I stopped at one of those packages.  I leaned ever to scoop it up in my little hand shovel and it moved!  Yes, it seemingly moved all on its own.  I rubbed my eyes and took another look.  It was just lying there, so I bent over again to pick it up and it moved again!!  Now, I know that I was not seeing things, so I watched it for a while and sure enough, it seemed to jump up a little bit every now and then.  I finally, after the uniqueness wore off, went ahead, leaned down, and scooped it up.  There was this little black bug under it.  It couldn’t have been more than a quarter inch wide or long.  It was a strong little bug with a huge appetite.  I sort of felt sorry for stealing its supper.  But not sorry enough that I didn't go back inside and eat my lunch.  Now, you all have a great day and enjoy your lunch, you hear?