Can you figure out what Alaska's mysterious "Ice Monster" is?

An employee for the Alaska Bureau of Land Management was checking ice conditions on the Chena River in Fairbanks last week when he noticed something moving against the current. The odd "creature," which spans 12-15 feet long, features an icy exterior covering what appears to be a submerged form.

“Our employees did not investigate. It’s kind of far out in the middle of the river,” the Bureau of Land Management - Alaska explained on its Facebook page. “Video was taken right by our BLM Fairbanks District Office facing downstream. We’re not sure what it is. We’re letting you all be the judge.”

In the spirit of the season, officials added some ominous music to the short clip and invited social media to take a stab at identifying the unusual creature. More than 700 people ventured a guess, with suggestions ranging from a lost shark to an Alaskan sturgeon to a rotting chunk of frozen moose hide.

"What is the likelihood that this is a whale that seriously lost its way from the Yukon river, transferring across other small river fjords into the Chena?" wrote one commenter. "Massive barnacles with ice on its back...But we would need some reference for the size of the animal first..."

As you might expect, there were several replies that what's shown in the video isn't a living creature at all, but just some trash caught between alternating currents.

"So far the most compelling explanation, one shared by experts at the Alaska Department of Fish and Game - Official and others, is that the video shows "frazil ice stuck to a rope that is probably caught on a bridge pier," the group shared.

Whatever "it" is, the Bureau of Land Management has enjoyed the speculation stirred up by the public.

"We've been excited about the number and variety of explanations offered for our recent video of the strange river object," they shared. "Your responses show how captivating the mysteries of the natural world can be!"