`Ball lightning could soon lose its status as a mystery, now that a team in Brazil has cooked up a simple recipe for making similar eerie orbs of light in the lab, even getting them to bounce around for several seconds. [..]
A more down-to-earth theory, proposed by John Abrahamson and James Dinniss at the University of Canterbury in Christchurch, New Zealand, is that ball lightning forms when lightning strikes soil, turning any silica in the soil into pure silicon vapour. As the vapour cools, the silicon condenses into a floating aerosol bound into a ball by charges that gather on its surface, and it glows with the heat of silicon recombining with oxygen.’
There’s also a ball lightning video.