I was in the back yard reading a book. I felt a inclination to look up. As I did I saw a bright reflective silvery cylindrical object (more of a line than two-dimensional) in the sky swiftly moving from West to East overhead in the clear sky. About the width of my index fingernail at arms length. It immediately morphed into a violent rapidly changing highly reflective shape as if it were a flat mirror randomly twisting about on three a axis gimbal. Not a bird, not a party balloon. The motion was violent. No rhythmic pattern. I expected it to move over the Giant Food store parking lot where I could see its silhouette, but instead it faded into the high altitude water vapor in the sky. It was much higher in altitude than I estimated, and much larger. My first thought it was about 60 feet up, but after seeing it fade away so rapidly, I estimate it to be at least a few hundred feet long, at least 30,000 feet up. It appeared to be traveling at several thousand miles per hour. No noise. No vapor trail. No wings. I'm 54, seen a lot in the sky I have been able to explain. Not this.