Either way you look at it, you got a wakeup call about leaving your property unsecured and out in the open. The dogs interest could be from the smell of a human trying to move the roll out of the way to get at other stuff. I'd clean up the are and remove any tools that could be used to get a lot further along to steal your property.
Meanwhile, my Dad enjoyed tying up my BIL's 140 lb pit bull to our Buick LeSabres's trailer hitch while we ate dinner. Until one day when the Buick wound up in the street. The dog just kept lurching his weight on the leather leash until the car inched it's way down the driveway, maybe less than 1/4" at a time.