It appears that the moon has somehow crashed into the northern state's Presumpscot River. It's a lot smaller than we previously thought, and also it's a flat circle made of ice.
An practically perfect ice disk is floating on the river's surface, slowly and mesmerizingly spinning away, the Portland Press Herald describes. The disk was first spotted Monday and has since grown to a massive 100 yards across — and it's also sparking some serious alien talk.
WATCH: A giant rotating ice disc is spinning in Maine's Presumpscot River.
This giant disk isn't a portal to the underworld, but rather a naturally occurring phenomenon. Scientists aren't entirely sure how the disks get so big, but they assume little bits of ice originally stick together and keep piling on as the floe rotates, a physics professor tells Maine Public Radio.
Admirers aren't encouraged to stand on the disk, but wildfowl certainly are. Rob Mitchell, who first spotted the circle, told the Press Herald there were "ducks sitting on ... this big Lazy Susan," adding that it "was a big duck-go-round." Check out more footage of the beautiful duck carousel below. Kathryn Krawczyk