25 Mysterious Sea Creatures That Are Bizarre and Rare


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Summer is coming in a few months and it’s all about sunshine, seafood, and mysterious sea creatures. Say what? Mysterious sea creatures?

Yes, that’s right! Mysterious underwater creatures that you never knew existed. Or even if you’ve heard about them, finally seeing a picture of what they look like will make you realize how surreal their existence is.

And we’re kidding, you won’t find these curious-looking animals while enjoying a swim. But since we’ve already piqued your curiosity, we’ll bring to light 25 mysterious ocean creatures to shed light on their mystery and satisfy your curiosity.

So here’s a list of mysterious sea creatures that are unknown, scary, interesting, and beautiful at the same time. We broke the list down into 6 brief categories so you can read through them easily:

Are you ready for a deep-sea adventure? Let’s dive right in!  

1. Unknown Sea Creatures


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After reading through the list earlier, you might be thinking, “With so many mysterious sea creatures, is 90% of the ocean undiscovered?” We get where you’re coming from and here’s the answer.

According to the U.S. Department of Commerce’s NOAA (National Oceanic and Atmospheric Administration), “more than eighty percent of our ocean is unmapped, unobserved, and explored.” So it may be true that 90% of the ocean is undiscovered.

But why is this so despite all the advances in technology?

Oceana, a non-profit dedicated to protecting the oceans, says that physics is the barrier to discovery. It’s been difficult to get the best settings of visibility, temperature, and pressure when it comes to ocean exploration according to Dr. Gene Feldman.

He’s an oceanographer Oceana interviewed who also shared that it’s easier to send someone to space than to the ocean floor. That’s a surprise!

Dr. Feldman goes on to say that, “The intense pressures in the deep ocean make it an extremely difficult environment to explore.” This is also why we can’t go to the bottom of the ocean floor. The pressure is too intense.

But scientists have found a workaround to this dilemma through technology like satellite technology, floats and drifter devices like remotely-operated vehicles (ROVs). Their efforts have borne fruit that led to the discovery of the unknown and mysterious underwater creatures we’ll be sharing with you.

So if you’re wondering if there are unknown creatures in the ocean, the answer is yes. Say hello to the creatures below.

Scientific name: Vampyroteuthis infernalis

It’s a scary name for a mysterious sea creature for sure but its nature is far from what it’s called. The vampire squid only eats dead plankton and animal matter that falls from the ocean’s surface.

It got its name because of its unique body that has dark-colored skin and connecting arms that resemble the fictitious vampire’s cape. The vampire squid also has another unique characteristic called bioluminescence, like twinkling light effects, that it uses to confuse predators. Unique, isn’t it?

And two years ago, it made it to the list of the unknown sea creatures of 2019 because of the species’ rarity and sightings. This mysterious underwater creature has only one species in existence and lives 3,000 feet under the sea.

Mysterious Sea Creatures #2: The Gulper Eel

Scientific name: Eurypharynx pelecanoides

Another mysterious ocean creature that made it to the list of unknown sea creatures of 2019 was the Gulper Eel. It’s also called the Pelican Eel because of the way it scoops food like a pelican and takes it all in with a big gulp.

But scientists think it inflates not just because of food but more because of defending itself when it feels threatened. As to when its complete characteristics will be confirmed is tentative because very little is still known about the Gulper Eel. What we do know is that these mysterious sea creatures have an appetite for tasty small crustaceans and a habitat 9,000 feet underwater.

Mysterious Sea Creatures #3: The Wakanda Fish


Source by: Reeffish – Own work

Scientific name: Cirrhilabrus Wakanda

Fans of Marvel’s Black Panther will be wistful as they learn about a newly discovered fish that’s been named after the movie’s fictional country, Wakanda. These mysterious underwater creatures have been named so because of their habitat that’s secretive and set-apart from the other species of fish just like Wakanda. It’s also aptly named because of the bright purple streaks that pigment its body like the suit that Black Panther wears.

The fish live 260 feet in the Indian Ocean’s “Twilight Zone” reefs, the area of the ocean where light barely gets in. So far that’s all the information scientists have. No wonder it’s one of the unknown sea creatures of 2019 when it was reported. We’ll get to know this little fellow better as scientists study it more through the years.

Mysterious Sea Creatures #4: The Tunicate

Scientific name: none yet

The Indian Ocean seems to be a treasure trove of mysteries from top to bottom. On the surface, an island called the North Sentinel is one of the most untouched places on earth.

Underneath its waters lies the Java Trench, one of the world’s deepest trenches. It’s where a new jellyfish species, one of the unknown sea creatures of 2019, was discovered by the Five Deeps Expedition.

The team believes this mysterious ocean creature is a tunicate. It’s a sea squirt that has a large tentacle that’s long enough to anchor it to the seafloor. It occasionally raises itself when there are seismic movements on the ground. They discovered the mysterious underwater creature 21,300 feet below the Indian Ocean.

2. Scary Sea Creatures


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Oceans are often perceived as an adventure to conquer or a romantic story to unfold. But have you ever thought about it as a setting for a horror story?

The scary sea creatures in the next section might change your mind as their looks show you the scary and strange side of the ocean. Check these mysterious underwater creatures out if you’re a brave soul.

Mysterious Sea Creatures #5: The Deep-Sea Lizard Fish

Scientific name: Bathysaurus ferox

A sinister smile and sinister eyes characterize this mysterious ocean creature called the Lizard Fish. It’s a deep-sea dweller that lives in the “midnight” zone of the ocean, 3,000 feet below the surface. It’s the level that receives no amount of sunlight at all.

Living in such deep waters where food is scarce has made it an ambush predator. It lies in wait for unsuspecting prey to come by and become its lunch. Razor-sharp teeth keep the unfortunate fish from swimming away and drag it deeper instead into the lizardfish’s mouth. No one is spared from this scary sea creature.

Mysterious Sea Creatures #6: The Frilled Shark

Scientific name: Chlamydoselachus anguineus

Wait till you get ahold of the frilled shark if you thought the lizardfish were bizarre mysterious sea creatures. The terrifying-looking shark is also called a “living fossil” because its species has been in existence for 80 million years and its similarity to ancient creatures from those periods.

That means they lived during the time the dinosaurs were alive! What a cool thought, isn’t it? It’s this prehistoric lineage that makes the frilled shark one of the most interesting sea creatures to study too.

This ancient predator and scary sea creature got its name because of its gills that have a frilly appearance. They prey on squids, fishes, and even other sharks as long as half its body. Its mysteriousness comes from its rare sightings because it lives 390 to 4,200 feet deep in the ocean. Few studies have consequently been made on it.

Mysterious Sea Creatures #7: The Fangtooth Fish


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Scientific name: Anoplogastridae

According to National Geographic, this Fangtooth is a mysterious underwater creature who lives the deepest in the ocean. It’s been discovered at a whopping 16,500 feet deep!

But it’s a small fish despite its menacing appearance and physical endurance. This scary sea creature can only grow as long as seven inches. They feed on squid and fish with their long fangs and huge mouths.

Mysterious Sea Creatures #8: Deep-Sea Angler Fish

Scientific name: Melanocetus johnsonii

Scary sea creatures like the deep-sea angler fish make you feel more afraid of the light than the dark when it comes to deep oceans. The famous glowing bulb on its head serves not as a guiding light but as bait meant to lure in food into its wide mouth.

Deep-sea angler fish are mysterious sea creatures that live as deep as 6,600 feet under the sea. They’re naturally rare because of the fragile life they live in that food and mates are rare in the deep ocean.

3. Interesting Sea Creatures


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Now let’s move on to mysterious and interesting sea creatures that have characteristics no other fish in the world has. Meet your new friends under the sea in the next segment.

Mysterious Sea Creatures #9: The Blobfish

Scientific name: Psychrolutes microporos

Did you know there’s such a thing as the world’s ugliest animal? It’s true. This mysterious ocean creature won the title because of its jello-like appearance and frowning face. It was awarded by the Ugly Animal Society in 2013 to raise awareness for the conservation of aesthetically-challenged animals like the blobfish.

When the internet came to know about it in 2013, the blobfish became one of the strangest things in the world to those who marveled at it. This is how it came to become a meme and a viral topic.

The famous blobfish that the internet has come to know was discovered a decade earlier in 2003. It was found by the research vessel NORFANZ and was one of the strangest things found in the ocean at that time.

And did you know it has a name too? Call him Mr. Blobby.

But despite its silly appearance, that’s exactly what makes the blobfish one of the ocean’s interesting sea creatures. Its physical features and how those body parts function are what allow it to conquer its prey and swim in the deep ocean. And the catch is, it looks very different under the water. It doesn’t look like a blob at all.

Interesting, right? Watch the video above from Science Insider to learn more about this plot twist.

Mysterious Sea Creatures #10: The Halitrephes Jelly

Scientific name: Halitrephes maasi

Did you know that one of the most interesting sea creatures in the world is the Halitrephes jelly? These interesting sea creatures look like a burst of fireworks under the sea and are truly a sight to behold. They live 4,000 to 5,000 feet deep under the sea and have been sighted near the Baja California Peninsula in Mexico.

According to the EVNautilus team who captured the incredible video, the fireworks effects are made by the animal’s radial canals that move its nutrients. The effects happen as the nutrients move through the bell of the jelly.

It’s one of the world’s most mysterious sea creatures too because little is known about it because the species is rare. Few studies have been made on it in effect.

Mysterious Sea Creatures #11: The Megamouth Shark

Scientific name: Megachasma pelagios

Did you know that not all sharks are meat-eaters? Contrary to the movie “Jaws” where humans are sharks’ favorite lunchtime, some sharks like the megamouth sharks filter-feed instead. They’re known to only eat plankton, jellyfish, and shrimp.

These interesting sea creatures are one of the world’s largest sharks too. They can grow as long as 16 feet in length with a mouth as wide as four feet. The size of its mouth gave way to its name.

Megamouth sharks are still mysterious to scientists because they live 15,000 feet in the sea and rarely come to the surface. Very few have been studied because of that.

Mysterious Sea Creatures #12: Halimeda Ghost Pipefish


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Scientific name: Solenostomus halimeda

What can be more interesting than mysterious underwater creatures that are here one second and gone the next? The Halimeda ghost pipefishes are here to say “catch me if you can” as they camouflage among Halimeda algae leaves.  

They’re unique and interesting sea creatures that mimic the look of their natural habitat’s algae beds. They feed on plankton and live for only a few weeks.

Their short lifespan and elusive nature have made it difficult for scientists to break the mystery of their camouflaging abilities. But when they get to breed these interesting sea creatures successfully, they’ll get to understand the Halimeda ghost pipefish’s genetics and break the code.

4. The Most Beautiful Sea Creatures


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Now here’s a good break from all the weird and frightening sea creatures we’ve been looking at. Next up are the world’s most beautiful sea creatures. Take a visual break in the next section.

Mysterious Sea Creatures #13: Mermaids


No evidence of the legendary mermaids has ever been found but they occupy our imaginations as one of the most beautiful sea creatures. And we don’t have to wonder why.

Being half-human and half-fish, mermaids are mesmerizing to look at. They add mystery, romance, and adventure to any story. So many legends and movies have been made about them that it’s hard to stop thinking about mermaids.

Since 90 of the ocean is undiscovered, who knows if we find one of these mysterious ocean creatures as we explore? But until then, enjoy their presence as iconic characters in stories and movies. Or more excitingly, as animatronic mermaids in museums and theme parks for a more realistic experience.

Mysterious Sea Creatures #14: The Narwhal

Scientific name: Monodon monoceros

Do you believe in unicorns? Well, we don’t but unicorn-like mysterious sea creatures like narwhals would be just as great. This whale is one of the most beautiful sea creatures because of the way it looks.

Narwhals look like whales that have a left-tooth that extends its way out of the mouth making it look like a unicorn’s horn. Its mysteriousness lies in its reclusive nature, difficult to reach Arctic habitat and the little-known facts about its ivory tusk’s purpose and properties.

Mysterious Sea Creatures #15: Leafy Sea Dragons


Source by: James Rosindell – Own work

Scientific name: Phycodurus eques

Australia is home to one of the world’s most beautiful sea creatures, the Leafy Sea Dragons. The bright colors and delicate shape of their bodies give it its graceful appearance.

The way they look serves as a way to protect themselves too. Their leafy look lets them blend in with the algae and keeps foes from preying on them. And though they look like seahorses, these mysterious underwater creatures have a closer connection to pipefishes.

Mysterious Sea Creatures #16: The Sea Butterfly


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Scientific name: Thecosomata

Another other-worldly animal whose appearance makes it to our list of the most beautiful sea creatures is the Sea Butterfly. The sea butterflies aren’t underwater caterpillars that became butterflies in the ocean, but they’re actually underwater swimming sea snails.

What makes them different from other sea snails are their feet that have adapted to the deep sea and evolved to lobes that serve as their “wings”. They use these lobes to swim and float around. Sea butterflies don’t crawl on the ocean floor like sea snails normally do.

These mysterious sea creatures’ unique appearance comes from their transparent thin shells that let observers see the internal organs underneath. Their short lifespans during captivity have made studying them difficult which is why only a handful of information is known about them.

5. Amazing Sea Creatures


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Here are some more good vibes from amazing sea creatures you’ve never seen before. Some may look odd but odd has never looked so good with these upcoming mysterious sea creatures. Check them out below.

Mysterious Sea Creatures #17: The Axolotl


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Scientific name: Ambystoma mexicanum

The Axolotl is a mix of funny, cute, and odd. It reminds you of space creatures that belong to movies like Marvel’s “Guardians of the Galaxy” or Pixar’s “Lifted”.

Axolotls are amazing because aside from their unique appearance, they have a unique trait that’s called neoteny. It’s a rare trait that lets this amphibian keep its larval features even when it’s reached adulthood. Neoteny gives the axolotl its distinct tadpole fin, feathery gills, and a wide head.

Though axolotls aren’t inhabitants of the sea, we included them in this list of amazing sea creatures because of their unique physical features and life. The axolotls’ natural habitat is Lake Xochimilco in Mexico City.

They’re quite a mystery too because of their ability to regenerate any part of their body. Scientists were even able to transplant one axolotl’s head to another successfully! Scientists also discovered that this amphibian has 32 billion pairs of DNA whose mysteries they’re still unraveling.

Mysterious Sea Creatures #18: The Dumbo Octopus


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Scientific name: Grimpoteuthis spp.

Another one of the world’s amazing sea creatures is dumbo octopuses. These animals got their name because of their distinct fins that look like the ears of Dumbo, the little elephant with big ears from Disney.

Dumbo octopuses are small even though their name brings the impression that it’s a large animal. They’re only eight inches long. National Geographic even reports that netizens call it the cutest octopus in the world. Their unique look and small size are what make them so appealing.

These amazing sea creatures live in the deep oceans and reside at 13,000 feet deep. In those depths, they feed on snails and worms. It’s this preference for the deep that makes them mysterious. They’re rarely sighted as they reside in the ocean depths.

Mysterious Sea Creatures #19: The Giant Squid

Scientific name: Architeuthis dux

Underneath the oceans dwells mysterious sea creatures like the Giant Squid. It’s literally gigantic as the biggest one recorded by scientists was nearly 43 feet long.

What makes it one of the world’s amazing sea creatures are its abilities and physical appearance. Giant squids can snag lunch as far as 33 feet away from them by using their two giant tentacles. Giant squids also have eight thick arms with suckers as wide as two inches and eyes as large as dinner plates.

And we’re not exaggerating, these are all true!

More facts about their way of life and biology remain a mystery because of their elusiveness. These mysterious sea creatures live in the world’s deep oceans such as the Atlantic Ocean and the Pacific Ocean. They’re known to reside at depths of 980 to 3,280 feet.

Mysterious Sea Creatures #20: The Giant Siphonophore

Scientific name: Apolemia

What comes to mind when we think about the word amazing sea creatures are details that go beyond the normal. The estimated 390-foot length of this giant siphonophore found off of West Australia’s coast is one such example.

Don’t be fooled by its glowing beautiful appearance though. This deep-sea creature is a predator with stinging cells that lie in wait for unsuspecting prey like crustaceans and fish to come along.

The giant siphonophore was found in the ocean in 2020 by Ningaloo Canyons Expedition. They’re a team made up of researchers from the Scripps Institution of Oceanography, the Western Australia Museum, and the Schmidt Ocean Institute.

6. Rare Sea Creatures


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Now we’re on to the last part of our trip. Let’s take a look at rare sea creatures like goblin sharks and vaquitas who are the world’s rarest marine mammals. Here we go!

Mysterious Sea Creatures #21: Goblin Sharks

Scientific name: Mitsukurina owstoni

Another treasure from the deep sea are rare sea creatures called goblin sharks. They’re also called “living fossils” like the frilled sharks because they’re the only representatives from the ancient family lineage of Mitsukurinidae. Their family line is as old as 125 million years!

Now that’s prehistoric for sure.

Goblin sharks aren’t known to be harmful to humans despite their fierce appearance. These mysterious ocean creatures feed most on squids, fishes, and crustaceans. They’re also known to live in the deep waters worldwide. Goblin sharks reside in areas as deep as 4,300 feet.  

Mysterious Sea Creatures #22: The Vaquita


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Scientific name: Phocoena sinus

Did you know the vaquita is the world’s rarest marine mammal? It’s so rare that only 10 individual vaquitas are in existence. This rare sea creature’s population declined because of drowning from the gillnets illegal fishing operations used.  

Vaquitas are porpoises that live along the Gulf of California in Mexico. They look similar to dolphins but their facial features differ. Vaquitas have dark colorations around their eyes and lips.

They’re mysterious sea creatures to scientists because not much is known about their lifestyle and history. Their very few numbers keep scientists from getting to know these rare sea creatures better. This is why scientists are working hard to stop its extinction and improve its quality of life.

Mysterious Sea Creatures #23: Kemp's Ridley Sea Turtle


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Scientific name: Lepidochelys kempii

Did you know Kemp’s Ridley sea turtle is the world’s rarest sea turtle? These rare sea creatures are inhabitants of the Gulf of Mexico on which they make their nests.

It’s so rare that there are only two living species from their genus (Lepidochelys). And only about 7,000 to 9,000 nesting females are left.

Mysterious Sea Creatures #24: Red Handfish


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Scientific name: Thymichthys politus

Frowning and caught red-handed, these red handfish are endangered and rare sea creatures from Southeastern Tasmania, Australia. They use their trademark “red hands” to walk around the seafloor. Those are its fins, in reality, though they look like hands.

Its rarity comes from it having only a possible population of 80 individuals. It makes the red handfish one of the rarest fishes in the world. These rare sea creatures’ decline in numbers comes from poaching and low reproductive rates.

Mysterious Sea Creatures #25: Basket Stars


Source by: Alexander Vasenin – Own work

Scientific name: Gorgonocephalus arcticus

Mysterious sea creatures always seem to come with a sense of rarity and basket stars are no different. These deep-sea dwellers live in the areas of the Arctic to Cape Cod and are found as deep as 3,937 feet (1,200 meters). Making them hard to find and rarely seen.

Basket stars live on the crustaceans that come their way and use their arms spines to capture the unfortunate prey. Their lifespan can be as long as 35 years.

Mysterious Sea Creatures & Us


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Getting to know all these mysterious sea creatures really opened our eyes to the wonders of nature, don’t you think? It also shows us that there’s always something new to discover.

So don’t stop learning and keep on seeking out new things. That’s the best way to grow and see ourselves become better people year after year. If you are interested in this kind of content, the blog Top 8 Swimming & Water Dinosaurs is also a good choice.

Lastly, the discoveries we explored also show us how we must be better stewards of this planet we call home. Oceans and seas may be far from our urban jungles but it doesn’t mean we shouldn’t be mindful of them.

Let’s do what we can to keep the oceans and seas safe from harm so these creatures can just thrive and flourish. After all, we live in the same world. When their environment flourishes, so do we.

Here’s to a better planet and a better us this year.

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