A Mid-Summer Night Mystery

As I have mentioned before, I've experienced several very strange things that I have no good explanation for in my life thus far. One of these incidents happened when I was roughly fourteen or fifteen years old. I lived in a town not far from here with my parents and siblings, on a side street just east of a main road. The house we lived in at that time was on a little hill and my bedroom was located on the west side over the garage. There was a west-facing window in my room from which I looked out over the driveway below. Beyond the driveway was a fence surrounding a neighbor's yard and their home beyond. Further west, beyond the neighbor's property was the aforementioned main road. My bed was positioned lengthwise along the west wall of the room, and I was in the habit of sitting on the end of the bed, elbows propped on the window ledge. Many an evening would find me in that spot, admiring the sunset or watching the cars go by out on the main street, on the way into or out of town.
One very hot and muggy summer night, I was gazing out my window watching for fireflies and listening to the katydids murmur. The rest of my family had retired for the evening. It was a week night, well after ten pm and all was quiet, but we did not have air conditioning in those days and I was too hot to sleep. The neighbor's home on the other side of the fence was completely dark. They were an older couple whose children were grown and gone, and I guess they too had gone to bed for the night.
Suddenly, without warning, a dazzling, bright light about the size of a soft-ball rose up from behind the fence right in front of me! It looked as if it was burning somehow, with white fire, like a sparkler that children wave as they run across lawns on the Fourth of July, but there was no hiss or crackling sound and not a soul was in sight. It was totally silent. It rose up a few inches above the top of the fence, only about 5 or 6 yards away from where I was sitting behind the window screen. It hovered for a second and then disappeared behind the fence. My initial reaction was one of intense curiosity. What the heck was that?, I asked myself. I had heard of "willow the wisps" and "St. Elmo's fire", rare phenomena related to swamp gas or electromagnetic anomalies. Maybe this was something like that. I'd read about something called ball lightning, but I recalled that it was usually accompanied by thunder storms, and tends to explode loudly shortly after forming. There was no sound to this at all. I didn't know anyone who'd ever reported seeing anything like this. I was sitting, calmly pondering this with no sense of fear or anxiety at all, when out of the corner of my eye, I saw it again. Moving up the street now, flashing brilliant white sparks, it rolled slowly along in the gutter. It did not appear to bounce at all, or veer off course as you would expect a natural thing might do. I sat puzzling over this, watching as it steadily approached the end of our driveway.
Then, it did something totally unexpected and utterly terrifying. When it reached the end of our driveway, it suddenly took a razor sharp right turn and started rolling up the driveway directly toward me. More later...