A video showing what appears to be a UFO whizzing past a commercial jet has been creating a stir on the Web.
Footage captured by a startled-sounding passenger seemingly shows a white bowl-shaped object flying over Seoul, South Korea, at high speed.
Later in the video the mysterious shape is magnified and slowed down.
But is the UFO sighting authentic or just a computer-generated hoax?
Whatever the explanation, the video - which has racked up almost a million views since it was posted three days ago - has divided viewers. The owner of the video has speculated that it could be a military drone.
Others humorously suggest that it is a giant frisbee or flying Mentos.
Watch the video and decide for yourself.