Minutes after taking the photo in the PiP I was amazed to see this cloud formation too. It is actually called a Lenticular cloud which are stationary clouds that form mostly in the troposphere, typically in parallel alignment to the wind direction. They are often comparable in appearance to a lens or saucer. Nacreous clouds that form in the lower stratosphere sometimes have lenticular shapes.

The second PiP shows the same formation a few minutes later, which to me, looks a little more like a UFO.

Of course I could be wrong about it being a cloud and it really was a giant UFO (˚◡˚)

Enjoy full screen.