A video posted on line apparently shows the mythical Icelandic creature Lagarfjóts Worm – Iceland’s answer to Scotland’s fabled underwater beast.

Cameraman Hjörtur Kjerúlf captured the giant, icy snake swimming in the Jökulsá í Fljótsdal river, which empties into Lake Lagarfljót.

References to the Lagarfjóts Worm, which is also known as Lagarfljótsormurinn (what’s with these tongue twisting Icelandic names?), were first recorded as far back as 1345AD.

According to Nordic legend, it was first a tiny worm which was put on a ring of gold to make the ring grow, Iceland Review explained.

When the owner of the worm returned, she discovered that it had grown enormous but the ring was still the same size as before.

In frustration, she threw both the worm and the ring into the lake, where the worm continued to grow even bigger.

Of course, sceptics, always spoiling the fun, say the video merely shows a torn fishing net which froze in the river.

But the sleek movements of whatever it is that was filmed suggests otherwise.

So, monster or frozen fishing net? You decide: