2006-06-30 - Lakeland, FL - Changing

I was driving south bound down North Florida Avenue approaching Lakeland Regional Hospital when I saw what looked like a large black trash bag had blown off the top of the roof of the hospital. At least that was my initial thought. I continued to watch it because I was sitting at a stop light right next to the hospital and it continued to move slowly and rise as it also appeared to change shape and form an eliptical shape. Then as it continued on to the West, it formed a more rounded shape. My second thought was that it was a large black bird of some sort but the more I watched it and began to follow it, the more I could see it was not. I knew there was something else to this object that was more than just strange. It seemingly began to rise but only noticable because there were points of reference on the ground that made it seem to be going higher. A jet passed a good distence above it. It continued to move West and higher in the sky as I followed it. I came to a point where it seemed to stop moving in a Westerly direction and just continued to move higher while sustianing its rounded disklike shape from my point of view from below it. I watched it for another 15 or 20 minutes until it became so high to a black pin point in the sky and eventually vanishing from sight. There were no lights and no other features to this object that I could observe other than it was black and dementionless as it distorted and changed shape. There was no blure as I could see its edges very clearly eventhough they had the tendency to move into and out of position. This is unlike any UFO I've ever seen before and completely silent.