Ball lightning
Ball lightning refers to mobile bright spheres sometimes observed during thunderstorms. Most observations of ball lightning are made during thunderstorm activity, within a few feet of the ground. A typical ball lightning is about as big as an orange or grapefruit, and lasts a few seconds. Visual sightings are often accompanied by sound, odor, and permanent material damage.[1]
Very similar, if not identical phenomena, occur in submarines due to electric discharge of direct current across a circuit breaker, and in high-power electrical equipment. Ball lightning is sometimes confused with St Elmo's Fire. St Elmo's fire is a corona discharge from a pointed conducting object, which must remain attached to a conductor, and which usually lasts much longer than ball lightning.