Major fear explained after man showed ‘terrifying’ true reality when dropping GoPro into ocean off cruise ship

People think they've figured out why many have a major fear after watching the footage someone collected by dropping their GoPro underneath a cruise ship.

Folks are scared of all sorts of things like spiders, wasps, heights, intimacy, snakes, vegetables, belly buttons, and the notion that a duck could be watch you at any moment.

For others it's a fear of the sea, that great mass of churning water which covers the majority of our planet's surface and is home to all sorts of things we don't even know about.

While phobias are supposed to be irrational, people who've seen footage of what lurks just beneath the surface are reckoning that those who have a fear of the sea are onto something.

YouTuber Odysseas Froilan dropped a GoPro under a cruise ship for a better look and the camera was almost immediately surrounded by inquisitive denizens of the briny depths.

Even if many of them just wanted a look at the new object in their world it was still a rapid welcome.

However, once the camera got settled it was rather peaceful down there are marine life got on with its daily business of swimming around looking for something to eat and viewers liked the 'naturally curious' nature of the fish.

Others said this was an 'absolutely adorable' glimpse at a world we don't normally get to see, but it was a different tune during the night.

That's when the sharks came out to play and sea life could only be seen for a brief moment before they disappeared into the darkness.

Another viewer said they finally understood 'thalassophobia', a fear of the sea, not because of the creatures but because of 'partially obscured huge objects in the water' as they explained the feeling of being somewhere other than the world they knew.

Are you scared of the sea, or what's in it? (YouTube/Odysseas Froilan)

Thalassophobia is a phobia of the sea, and can be set off just by looking at a picture of it or even thinking about the sea.

Most people have a phobia and a fear of the sea is among the more 'popular' ones, for lack of a better word.

Exactly what causes phobias can differ from case to case, but some studies have indicated that phobias can be passed down through the generations while a person's experience in life can also give them some fears too.

Indeed, when it came to a fear of the sea many people found that the movie Jaws left them utterly terrified of going near water.

While most people were afraid of the sea for fear that a shark might get them, others got the jitters around pretty much any body of water and didn't even want to get into a swimming pool.