Resolved - just a bright worklight on a harvester at night appearing as an "orb"

A friend of mine, who moved out to a farm last year (so is unfamiliar with what she could expect to see) had a “UFO sighting” and is looking for a good explanation. I have one or two reasonable ideas, I just thought it might be good to get some independent skeptical opinions from folks with a little bit more personal experience, of, perhaps, cornfields at night. here’s what she said: “Theories?? I live on a farm in the middle of nowhere right now and the property I live on is surrounded by cornfields. Last night I saw some weird ass alien shit and I’m not sure what it was. So I am looking to see if someone who is familiar with country life can explain this.
So none of the corn around the house has been harvested yet. I heard what sounded like a tractor or large vehicle nearby so I went on the porch and heard it coming from the cornfield. At first I thought a tractor was probably driving through, but when I looked further I didn’t see any tractor rise above the corn, and there was only what I can describe as a halo of light just above the corn.
So then I thought, maybe there is a random vehicle driving around in the corn and light is reflecting up. But why would a vehicle just be driving around in there and not know where the hell they were going, plus the sun was completely down. So I just stood there staring at this light halo hover above the corn and then the light suddenly disappeared. It was super fast too. Like it wasn’t a dimming and then disappear, it was like POOF. BUT, I still heard the vehicle type sound for about ten more minutes, but the light was gone.
So do small tractors that can’t see above the corn just randomly drive around at night? What is the light halo thing? Is there some piece of farm equipment that has something like that?”

ground fog, and other kinds of interference and defuse light and create halos. Ever flown in a jet over a cloud and see the weird orb around the shadow. Light can do weird things.

Way back, couple years out of high school, I was hitch-hiking up Highway 1 north of San Francisco up near Bodega Bay, past sunset, rolling hills, winding two way road, not much traffic, but thanks to the fog rolling in, those light cones could be seen streaking though the sky for miles.
Thing is the few cars there were, were driving a very curving road so that head lights would dance across the fog, then with multiple cars in both directions, there’s be a flurry of these intermingling pairs of light dancing past each other and then past me. Then I’d be left to walk down the middle of world famous California Highway One feeling like the king of the world.

One of the most fantastical light shows I’d ever seen. It’s still seared into my memory. Then I got a fun ride by a fun young couple, and even wound up on nice couch to sleep out the night. Next morning and a cup of coffee and sincere thank you and off I was to catch my next ride.

Another time, dark night again, another place, going through a snowy mountain town, there were these fantastical flare ups and a brilliant glow suddenly filled the valley with an amazing light and there was even a weird sound I couldn’t make out. Reminded me of a movie scene of a space ship or something. I didn’t think it was a space ship, but it was a total mystery and it totally fascinated me and had me taking a good little detour as I was trying to figure where it came from and then to get closer and figure out what it was. As I did get closer it started making sense, then I wound up looking at this little rail yard where a guy was arc welding.

Light plays lots of tricks.

I like this story because of the corn. and the halo of light.
I have a place in my field that I grow Corn. shortly after the sun goes down the temperature drops and the vapor turns to low lying Fog
if a light is lower than the height of the corn the Fog lights up and is round shaped.
If the light turns off the round shaped light goes magically away. This may or may not be the case here but Could be. That is of course if vehicles has head lights. and can be turned of at some point whale still running. Still could be an Unidentified halo light that make a vehicle sound in the middle of a Corn field?
I like the UFO idea better. with that the story is somewhat like a car with the lights on driving around in a corn field at night. An I would never do that.