Footage uploaded to YouTube of the “UFO” filmed just outside Dos Palos off Interstate 5 in California, has been viewed more than 10,000 times.
The video shows a motorist pulling over next to a small road before filming a distant white object.
However, when the camera is later zoomed in it appears to have a green tinged trail coming from it.
It has been suggested by alien conspiracy theorist YouTube channel Third Phase of Moon, the object is hurtling into Earth’s outer atmosphere before the clip comes to an end.
The video narrator says: “In the beginning, I thought you may as well dismiss it as a weather balloon sighting.
“But the closer you look at it, the weather balloons don’t act this way.
“It continuously morphs and the colours are quite amazing.”
Viewers had mixed reactions.
The ‘trailing UFO’ but it has emerged it dates back five years.
One YouTube poster said: “Weather balloon? You kidding… it’s obvious that that is some thing out of this world.”
A second added: “Wow, I am speechless.”
However, a third added: “This is so clearly fake.”
Third Phase of Moon features on a number of UFO website and YouTube channel black lists created by sceptical ufologists, who claim they have screened hoax and misrepresented footage.
Ufoofinterest.org has compared the sighting to other balloons and says it is the same.
In the beginning, I thought you may as well dismiss it as a weather balloon sighting. But the closer you look at it, the weather balloons don’t act this way.
Brothers Brett and Blake Cousins, who run the channel, deny this, claiming to be genuine researchers.
However, Scott Brando, who runs hoax-busting website ufoofinterest.org, says he tracked down the original footage… and it was a confirmed weather balloon filmed over Dos Palos, and videoed FIVE years ago.
Mr Brando provided Express.co.uk a link to the event as it was first published on YouTube in July 2012.
At the time, the uploader also claimed it was a UFO.
However, Mr Brando also provided links to other footage comparing the sighting to a deflating balloon.
He told Express.co.uk: I think we are seeing something like this, similar to a super pressure balloon deflated reflecting sunlight.”