Image via Karen Racette.
It looks a lot like a UFO … but it’s what’s called lenticular cloud. These lens-shaped clouds typically form where stable, moist air flows over a mountain, and they can appear and disappear quickly. Karen Racette captured this one floating over Butte, Montana on October 7, 2019.
More photos of lenticular clouds, plus a word about how they form.
Source:
https://earthsky.org/todays-image/lenticular-cloud-montana-photo