The Ancient Astronauts Theory[]
So Jean Jacket being an angel is a popular theory that I can definitely see because it reminded me of the Wheels mentioned in the Book of Ezekiel and the biblical description of the end days in Revelation. A popular theory, but while I can subscribe to the idea that Jean Jacket is an alien, I think it was brought to Earth by aliens. When you really get down to how JJ has strict biological demands to be met, it would seem unlikely that it could travel through space on its own. But if JJ was brought here, what race of aliens would do such a thing?
Remember how Angel talks about Ancient Aliens on a tangent? While it would seem to be a little joke, what if he was right if roughly 97.7% that is? Yes, an ancient race of extraterrestrials did arrive on Earth and advance humanity, but what if they were approximately the same as humans?
The recurring theme of the movie is the lengths people would go to achieve spectacle even when it puts their health and lives at risk like with that TMZ guy. While the aliens I am proposing are advanced, one of their main drives is seeking entertainment and achieving spectacle. Would be hilarious if it turns out the aliens are more or less film directors. Thus, JJ was designed as a means of achieving spectacle by the aliens and they just sat back and watched their creation eat humans for the lulz. Yeah, they would not be benevolent in that scenario. They would also instill the desire to capture such a spectacle in mankind leading to technological advances, especially when it came to cameras and video recording.
That would mean that there are legitimate UFOs (or UAPs) out there while JJ is merely copying the appearance of one but instead of using a tractor beam it instead creates whirlwinds to gather prey.
But of course, despite believing themselves superior to mankind, they screw up when JJ becomes too uncontrollable and they are forced to cut their losses leaving a homicidal, shapeshifting anomaly on the Earth. Overall, the aliens were also using JJ as a living prop in much the same way Jupe was.