Ball lightning, artwork. Photography. Britannica ImageQuest, Encyclopædia Britannica, 25 May 2016.
quest.eb.com/search/132_1218363/1/132_1218363/cite. Accessed 15 Nov 2017.
This atmospheric phenomenon is most often associated with thunderstorms. It consists of luminous spherical regions of electrical energy that move through the air and have been reported to explode, with sometimes fatal effects. It is not clear what causes it, though it is sometimes confused with St Elmo's fire.