Black and shiny object flying over Denver CO

I was sitting at my desk playing around on the computer with the blinds open.  My window faces out to the East and I have a pretty good view of the sky from where my desk is at my house.  
I saw something black and shiny heading towards my house about 6-9 thousand feet up.  Lower than your usual aircraft coming in to land at DIA.  As it flew closer, I could see it tumbling over itself repeatedly and thought maybe it was a balloon at first.  But as it approached closer, I could see the sun reflecting off it very brightly and could easily tell that it wasn’t a balloon.  It started to get a little larger as it came closer and I ran outside to get a better look.  I am so glad I did that because what I saw next confirmed what I was hoping for all along.
As I stood on my porch, I was able to see this thing pretty well at that point.  It was very black and shiny and was shape-shifting from a star-like object, into a triangle object and then into something I cannot even describe on any level.  But it changed shapes as it continued to tumble over itself.  But every time it tumbled, you could see something different going on, almost as if it needed to tumble in order to accomplish a particular task.  I don’t know…that’s the best way I can describe it I guess.
At any rate, after watching this for 1-2 minutes, I watched it for as far as I could before it flew completely out of sight.  However, someone from downtown Denver should have been able to capture this thing well depending on his or her location.  It was heading towards the news stations so they should have been able to see this thing too. I hope someone reports it besides me.  Oh yeah, the camera on my phone wouldn’t have captured it as my phone is almost 4 years old.