Chrome diamond craft that transformed into a shpere

Saturday, January 22, approximately 3-4pm.  Leaving Montesano Washington and driving on Highway 12, going to Aberdeen. Driving on the straight stretch of highway I noticed an object in the sky.  Roughly 100 feet in the air was a chrome, diamond shaped craft in the sky. It was three dimensional and from my angle I could see its depth and edges. It looked to be about the size of an old Volkswagen Beetle.
After a few moments the craft started to shrink and its corners rounded out, and it fully transformed into a much smaller sphere. Within an instant it was completely gone.  The entire duration of the sighting was approximately 6 full seconds. I was in a state of shock and too startled to even consider pulling over and trying to take a picture. I was lucky that I didn't crash while watching it. The feeling of shock and confusion lasted long after the event.
I had gone home and journaled my sighting to preserve the details; and I consulted my journal while writing this report. I'm submitting this report to both MUFON and NUFORC.