The cause of a blinding light that spooked residents of a southern town in Russia remains a mystery, with speculations ranging from a cloud-measuring device to an alien invasion.
The pulsing light that briefly bathed the city of Stavropol white and blue on Monday night was caught on video by a dash cam mounted in a car, ABC News reports.
The burst of light also reportedly knocked out some streetlamps in the city, as seen in another webcam video.
The strange event has become even weirder after nobody was able to offer an explanation or plausible cause.
Local scientists have ruled out that natural phenomena could have caused it, ABC News reports.
"This flash cannot have been natural," Svetlana Solovyova, chief analyst at the Stavropol Meteorological centre told local media.
"It wasn't a meteorological event. There wasn't a storm," Natalya Klimenko, an analyst at the centre, told ABC News. "More likely it is something made by a human being."
Theories to explain the event have included the huge Russian military exercises, which are currently underway involving 80,000 troops;, while others believed the lights were the work of aliens.
In 2014, a huge blast turned the sky orange over Siberia and in 2013 a massive meteorite exploded over Chelyabinsk, blowing out almost every window in the city.
Scientists have concluded that the beam of light was not a meteorite because it would have been detected by radar.
Yuri Varakin, a local meteorologist, told ABC News that he believed the lights were most likely caused by a special high-powered projector lamp used by airports to measure the height of clouds.
An official at Stavropol airport confirmed to ABC News that the device was used on the night of the flash because there were thick snow-clouds.