"This was his aura, a cold halo of chemical electricity that encircled him immediately before he was struck by a full seizure."
Creative Commons Attribution Share Alike22°-Halo - Credit: Andrzej Barabasz (Chepry)
 Epilepsy is a disorder that results from the generation of electrical signals inside the brain, causing recurring seizures, with various symptoms including distortion of sound and images, and bright flashes of light.   Some people simply stare blankly for a few seconds during a seizure, while others have full-fledged convulsions.