Ball lightning
From Tardis Wiki, the free Doctor Who reference
Ball lightning was a rare meteorological phenomenon that manifested itself as flying, glowing orbs of energy. While under the control of Kaagh the Slayer, Nicholas Skinner mentioned ball lightning as a cover-up for the sighting of Sontaran drones the night before. (TV: The Last Sontaran)
Ball lightning occurred on Kirithon. (PROSE: Timewyrm: Apocalypse)
