If it’s an April Fool's joke, it’s a few days too late.
A mysterious round white object was filmed whizzing around a passenger plane above Seoul, the capital of South Korea, on April 7.
The clip, which has been uploaded to YouTube, begins with the ‘craft’ at the bottom of the screen, keeping pace with the passenger plane.
When the UFO accelerates he can be heard making some sort of exclamation, as if trying to draw someone’s attention to it.
The video was uploaded by YouTube user ‘Crazybreakingnews’, who commented: ‘It looks a little bit strange and not really similar to the other videos. If it's really real and not a fake, it looks like a kind of military drone.’
Several YouTube users are convinced it’s a UFO of some sort, but others remain sceptical.
Psued0Name said: ‘When stabilised, it is easy to see what is going on with the video.
'The edges of the UFO are not blurred like all of the other background objects, it seems like a separate effect from the background, and in fact you can see edge noise on the shape of the UFO indicating it's a fake.
'It doesn't even look right if you start to look at it hard, especially slowed down frame by frame.’
User vicariousjojoe agreed, writing: ‘People, you should know by now what is fake and what's not. You can always tell by the way the camera moves and zooms.’
Possible UFO activity has recently been sighted much closer to home, with a star-gazer filming intriguing footage of a glowing UFO, which he says he spotted hovering over the Thames Estuary in February.
The man, identified only as Space999dude, recorded the phenomenon as he drove past the river at night, he said.
The mysterious, oval aircraft can be seen suspended in the air displaying several amber-gold lights of varying sizes.
A Russian MP has asked an eccentric regional leader to explain his behaviour after claiming on state television that he was visited at home by aliens in a UFO, media reported last
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