Strange Creature Filmed Under Frozen Pond in Lithuania

Last night, I found this strange video of some kind of creature or natural phenomenon. It’s from Lithuania, and the author says he was walking near a frozen pond when he came across a thawed area near the middle. He went to investigate and found something very strange. Here’s the description from the video author:

So I was walking with my dog in the evening just before sunset, we were travelling into vast fields of nature to escape common modern view.

By accident I found a pond. It catched my interest since i saw a waterhole in the middle of it. Usually people drills waterholes in their ponds where fish lives, at winter time, so fish can breathe.

I thought I will see some fishes and stuff… But as soon as i came closer, I noticed that it was evaporating. You can’t see this in the video since I was filming with my phone which has not a high resolution camera.

When I stepped on that frozen pond, farther away from that waterhole (where i was standing) ice was 20 centimeters thick or even more. And that waterhole looked like it was melted with fire or something… You can see around that waterhole that there is snow or maybe ice particles blasted away from the center of this waterhole.

It is not volcanic activity. In the middle of Europe, Lithuania, there are no volcanoes or underground volcanic currents. Plus water would be boiling. There are no pipes in the middle of nowhere, so not a damaged pipe…

Natural Gas or oil? Impossible, it is not hot and why only the part of this whole pond is melted just above this thing/activity-reason?

At first glance, it looks like a jellyfish, but it is not. What was really there is still unknown for me.

What do you think it is?