There are a lot of people out there who are terrified of things in the deep blue sea. Who are so terrified to even step foot into the ocean or sea, because they are certain that there are things lurking down there that are going to snatch at their feet.

The truth is, there is. There are thousands of terrifying deep-sea creatures and sharks that are enough to scare even the toughest person. The good news is that they usually stay way deep down in the ocean, far enough that they will never come near you.

They are also not the only ones. Sharks and sea creatures have been around since the beginning of time. While they may not be around anymore, these prehistoric sea creatures and sharks are enough to send the chills down anyone’s spine and be very glad that they are not swimming around anymore.

20 Scaleless Doesn't Mean Less Scary

This shark is actually considered the first “true shark.” The good news is that it lived 380 million years ago.

What makes this shark a little creepy is how much it actually resembled a fish. It had a fish-like head and had seven gills instead of the normal 5 that sharks today have.

19 Snake + Shark = Nope

The spiny shark was interesting because it was almost a cross-species between a shark and a bony fish, think like a tuna.

This was one of the first animals to have a jaw, which scientists have been able to see through fossils that were collected. It had a cartilage skeleton like a shark, but it had a bony spine like a fish.

18 As If Eels Were Not Scary Enough!

Eels are scary enough without adding the work shark to the end of it. Luckily, this was an ancient freshwater shark that did die out 202 million years ago.

This shark would only grow to about a meter in length. It also looked more like an eel than the sharks we know today. Oh yea, and its spine was venomous.

17 Jaekelopterus, Stay Away

Sometimes, we are left not knowing a lot about things that lived so long ago. These things were huge. They measured in at over 8 feet long!

Some say that these were venomous, but there is no scientific evidence that shows us that any of these species had poison.

16 Tully Monster ... What Is This Thing?

The Tully Monster is one of the oddest sea creatures, which can make it even more terrifying. Scientists can not even agree on what this was based on fossil finds.

There is one thing interesting about this creature and that is that scientists can not decide whether this creature had a backbone, or if it was lacking one. It did have a claw-like structure and two rows of teeth.

15 Greenland Shark May Look Gentle

Here is a terrifying fact: the Greenland shark is still alive today. Since it has had a lifespan of over 400 years, it is considered a part of history.

The secret to how this guy has lived for so long is his slow nature. Experts do not even know how he catches seals because he swims so slow.

14 Swim Away

The Anvil shark may look terrifying, but it was actually really small. It was about the size of a rat, but its dorsal fin was terrifying.

The good news is that this shark lived 360 million years ago. The anvil-shaped fin was only found on male sharks, so experts believe it was part of a mating ritual.

13 These Were Very Real

One of the reasons so many people are afraid of sharks is because of all their pointy teeth. They wouldn’t want to come near this shark.

This shark lived 300 million years ago and was about the size of a great white. It is the only animal known to have ever used a slashing wound as a hunting technique.

12 The Infamous Meg

Thanks to all the movies and documentaries on Shark Week, most people know the Mega-toothed shark as The Meg.

This shark lived 23 to 2.6 million years ago, and its fossils have been found nearly all over the world. The Meg is known for its size and its ability to eat everything that it came across.

11 It Looks Like A Cartoon, But It's Not

This is one of the oddest-looking sharks, and one of the most terrifying. The buzzsaw shark lived 290 to 250 million years ago.

This shark is most famous for its spiraled tooth pattern. The buzzsaw shark was one of the first sharks that was able to grow back teeth that had fallen out.

10 Fang Blenny, Don't Let The Humorous Name Fool You

We are going to take a break from sharks and talk about other things in the water that are horrifying. The Fang Blenny was a finger-length coral reef fish, but it had a surprise.

This creature had two huge canine teeth coming out from their lower jaws. This fish disguised itself as a harmless cleaner fish until it was ready to attack.

9 Vampire Squid ... Nope!

They may be called vampires, but they are not the mythical kind. These were real creatures that lived, and they scavenged plankton and crustaceans.

The name comes from their dark, webbed arms that looked like a spooky cape. While they didn’t pose a threat to humans, they were creepy enough that we would stay away from them.

8 Sea Lamprey

A Sea Lamprey had a lot of things in common with the other vampiric creatures, but they did not bite. Instead, they were able to cling on using powerful suction.

Instead of having a normal mouth, they had a suction snout, giving them their terrifying appearance. They acted like a leech and used their snout to latch on to other creatures.

7 The Word Parasitic Is Never Good

Parasitic Barnacles are a creature that will have you itchy just reading about them. When most people think of a barnacle, they think of small crustaceans with a hard shell.

These barnacles would infest other types of crustaceans. They would latch on and grow much like a tumor. They would make their victims overeat, hence feeding the barnacle.

This name almost gives us the false sense of security that this is a cute, little sweet shark. However, it is anything but. The name comes from the little cookie-shaped bites it would leave in its prey.

These sharks are not very big, but they can do a lot of damage if they want to. The good news is that they don’t really tend to attack humans, so your swim is safe.

5 Hello Jurassic Park!

This is an animal you would expect to see in Jurassic Park. The actual size of this creature is not entirely known, but they think it was around 20 feet long.

These dinosaur-like sharks had very pointy teeth and they were big enough to eat a person whole. Which I think is a nightmare we all have about these large sea creatures.

4 It Only Looks Like It Is Smiling

This may look like a cross between a shark and a crocodile, but it is actually a whale. It may be the scariest whale we have ever seen.

It was a prehistoric predator of whales and they were found to be between 50 and 85 feet long. It is known for being the closest a whale species has ever come to resembling a snake.

3 Out Of My  Nightmares

There are very few people who like normal scorpions, but can you imagine a huge one that swims in the water?

These creatures have officially been extinct since before dinosaurs even roamed the earth, and we are thankful for that. Their closest living relative is the horseshoe crab, which is not as scary.

2 "It's Like A Tank"

These creatures were more like a tank than a sea creature. The scariest thing about this creature is that it had a bite force of 8,000 pounds. This means that was in the same group as a T-Rex and a Crocodile.

This creature also did not have teeth, per se, it had boney ridges like a turtle, but that did not stop it from chomping down with a powerful bite.

1 Giant Is Not Always A Good Thing!

Stingrays are still around, but they are more of an average size. While some may be scared of them, they are generally very gentle and beautiful the way they soar through the water.

There was a giant version that was much more terrifying. They would grow to be 17 feet across and had a 10-inch poison spike in their tails. Something you would definitely want to stay away from.