Why you should be concerned if you come across 'finger of death' while swimming in the ocean

You may already have a fear of the ocean and deep sea, and we're here to make it worse. Sorry.

It's mind-boggling that 71 percent of our planet consists of water, yet we've only explored five percent of our oceans.

Whether it be the viral video of the 'demon fish' or the thought of sharks alone, it's completely understandable to be freaked out.

It would be fair to label the deep sea as the unknown, but it feels like the more we do learn about it, the scarier it gets.

Footage of a phenomena that occurs below sea ice has opened the eyes of many viewers on YouTube.

While you may not come across it if you're having a dip at the beach, it really shows the capabilities of wildlife in the ocean.

Doesn't look very friendly, does it? (BBC)

Perhaps it's just the tip of the iceberg.

Originally uploaded by BBC Earth, the video shows something described as the 'ice finger of death' coming from the ice above, towards the sea floor and wildlife living on it.

What is a brinicle?

The scientific name for the scary tube that grows from the layer of ice is a brinicle, and they get their nickname because they kill marine life by freezing them.

Brinicles are found in the polar regions of our planet, and can only be found below blocks of sea ice, freezing everything in their path when they reach the ocean floor.

How do brinicles form?

When the sea ice cracks, it leaks brine into the ocean and as it is more dense, it sinks and freezes the surrounding seawater.

In Antarctica during the winter months in particular, not only does the continent double in size, becoming bigger than the USA, but its average sea temperature of -2°C is still 50°C warmer than the surface.

The stark difference in temperature means that when the tube of ice grows downward from ice exposed to the surface, it has deadly consequences.

Brinicles engulf and freeze creatures such as starfish, urchins, and other members of marine life.

They are said to be quite fragile though, while being a rare observation due to the specific conditions require for brinicles to form.

Don't think there are many brinicle fans out there after this (BBC)

Taking to the comments, one user said: "That is the most sinister looking piece of ice I have ever seen."

Another added: "This looked like a scene from a sci-fi/horror film. High praise for the people who filmed this awesome, and slightly horrific, video."

A third pointed out: "It's like a fairy tale movie with an ice witch dipping her finger to use her curse."

Well, if you were planning to go deep sea diving in Antarctica, there's your warning.