Nyusu English YouTube A small group of thousands of snowballs found on a beach near the village of Nyda, in northwest Siberia.

At first glance, the circular objects in the image above might seem like Jurassic Park dino eggs, or alien pods ready to hatch and wreak havoc on the world.

But it’s really sort of a kid’s dream come true ― and maybe some adults, too. Imagine waking up one day to the sight of thousands of snowballs scattered on the beach near where you live. How long would it take you to find yourself in the middle of the best-ever snowball fight?

That was the sight that greeted residents of Nyda, a village near the Arctic Circle in northwest Siberia at the end of October. The cold spheres ― stretching 11 miles along the coast ― ranged in size from a tennis ball to nearly 3 feet across, according to The Siberian Times.

“We were all very surprised,” one local citizen told the paper. “Many people believed it only when [they] saw with their own eyes. This has not happened previously. And there was not so much snow for them to form. It’s so interesting.”

A village administrator, Valery Akulov, offered a natural explanation to local media. “When the water in the gulf rose, it came into contact with the frost. The beach began to be covered with ice. Then the water began to slowly retreat, and the ice remained. Its pieces were rolling over in the wet sand and turned into these balls,” Akulov said.

Google Maps This map shows the location of the Siberian village of Nyda, where thousands of snowballs of varying sizes showed up.

The BBC reports the circular objects “result from a rare environmental process where small pieces of ice form, are rolled by wind and water, and end up as giant snowballs.”

This oddity of nature has cropped up before.

In 2010, floating ice spheres were seen near South Haven, Michigan, at the Great Lake:

Three years later, more ice balls were spotted along the shore of Lake Michigan in 2013, and still again, in 2015, Lake Michigan was the target of many frozen circular boulders, as seen in the following video:

So, if you happen to plan a winter vacation in Siberia, or even closer on Lake Michigan, don’t forget to bring your gloves and dress warmly.