There could be thousands of undiscovered creatures in the sea - here are the most terrifying ones we know about

• Some of the most terrifying sea creatures live deep down in the ocean - and there could be thousands more that we have yet to discover.
• If you dive 140 meters underwater, you could see a magemouth shark and 300 meters down, you might find a Japanese spider crab.
• The blobfish is found 900 meters underwater and was voted the world's ugliest animal by the Ugly Animal Preservation Society.
• Watch the video above to see more of the scariest animals of the deep ocean.

Do you like to swim in the ocean? It's great until you feel something brush your feet. Sure, it's probably a scrap of seaweed. But, it could be one of the hundreds of alien-looking aquatic animals living beneath the waves. At least, the ones we know about.

The following is a transcript of the video.

A lot of people aren't comfortable swimming in open water. I mean, you never know what lives in the water beneath your feet. The ocean holds many bizarre deep-sea monsters.

As you dive 140 meters underwater, you might see a megamouth shark. Sure, they look scary, but those 50 rows of teeth are for filtering krill.

The Japanese spider crab is happy to welcome you to 300 meters down. These massive crustaceans are thought to live to 100 years old and are a Japanese delicacy.

Even deeper is the Pacific blackdragon. It uses its chin barbel as a lure to attract small fish.

Another hundred and 50 meters down, we meet the vampire squid. It has bioluminescent organs called photophores that produce flashes of light and prefers free-floating debris from the surface to blood.

Look, here comes a blobfish! This thrilling deep-sea fish was voted the world's ugliest animal by the Ugly Animal Preservation Society. But its jelly-like skin looks much more natural at 900 meters.

The deeper you go, the more alien things look. Goblin sharks are believed to be unchanged for 125 million years, making them living fossils. They can launch their jaws forward to grab prey.

Down here, we enter the midnight zone, where no natural light can reach. You might also pass Tiburonia granrojo, or 'Big Red', one of the largest jellyfish in the world.

The fangtooth has teeth to spare, the largest of any fish. It can't even fully close its mouth.

The Sea Devil is the quintessential deep-sea anglerfish. Its bioluminescent lure attracts prey close to its massive jaws.

At 1,500 meters, the Frilled Shark looks closer to an eel. Its needle-like teeth hook squid ½ its size, and its jaws can gulp them down.

The barreleye looks upwards through its translucent head. It recognizes the silhouette of prey in the dim light.
But it should watch out below for the Ghost Shark. Its body is covered with sensory organs that detect motion in the surrounding water.

Down at 2,200 meters is one of the biggest residents of the deep. At 14 meters long, the colossal squid is the largest known invertebrate. Its arms have sharp hooks, which it uses to catch prey and fight sperm whales.

Deeper down are giant isopods, super-sized crustaceans. These guys are closely related to common pillbugs.
As we go deeper, we enter the Hadal zone, where life is less common. But you can still find some extreme life forms as deep as 7000m under the surface, like our friend the sea spider. It sucks up worms from the ocean floor with it's proboscis.

There are potentially thousands more undiscovered creatures swimming around under us. Who knows what else might be living down there?