I think one of the frequent dog walkers dogs saw a snake started barking and the snake lost its cool. What kind of snake is a mystery. Bullsnakes either shoot off ahead across the road or do a 180 and head back in the field. The pattern isn't right for a coiled rattler. The larger disturbed area at the tail I find interesting. It looks like some tail shaking transpired. The other photos almost look like two snakes, one large and one small.