I was looking out my window. When a black mass floated up into the sky directly in front of me.

This black undulating mass. There was no sound. No lights. If floated over a Uhaul facility. It looked at first to be about the size of a person. But it seemed to remain the same size no matter how far it got away from me. I considered that maybe it was a plastic bag. But, it was remarkably steady as it floated around. Unlike a bag in the wind. The black mass floated up over the Uhaul facility (from my perspective at the window). Then it floated east. Toward the Air Force residential housing area. Where it floated up through the cloud cover. Where it vanished.
This all happened in about 15-20 minutes. And I watched it the whole time. At one point it flew in such a way that a tree was blocking it from my view. I waited it out. And it came back into full view. At about the half way point of this 15-20 minute time period it was visible to me.
I also considered that it might be a drone. But there were no lights. Just an undulating black mass that seemed to change size as it floated.
It did not defy physics in terms of flight characteristics. It floated about very smoothly.
When I first saw it there seemed to be a bit of a trail. But after that there was nothing but the black undulating mass.
I did not attempt to take a picture because I have a screen in my window. I do not know if you've ever attempted to zoom while filming through a screen. But it is not worth the effort.