Are Ball lightenings UFOs?

 Ball lightning is very hard to reproduce under laboratory conditions, so for now it is not believed to be an actual phenomenon. Still, some people claim to have seen them, so I guess some can be UFOs, and some are not, in which case they would be some kind of atmospheric phenomenon.

UFOs show themselves on purpose and they can take any shape they desire. But they can also go totally incognito and not be seen by anyone.