10 Creepy Deep Sea Creatures You Didn’t Know Existed

Prepare for a spine-tingling plunge into the deepest, darkest corners of the ocean, where the real-life monsters of the deep lurk far below the waves. The deep sea, a realm less explored than outer space, is teeming with creatures so bizarre and terrifying, they seem plucked from the pages of a science fiction novel.

Meet the colossal squids with eyes as big as dinner plates, ghostly fish that glow in the dark, and bone-eating worms that feast on the skeletons of dead whales. Ready to explore the unknown? Here are 10 scary deep sea creatures you probably never knew existed, each more eerie than the last!

1. Sarcastic Fringehead

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Despite its humorous name, the sarcastic fringehead is a force to be reckoned with. These small but fierce fish, measuring up to 12 inches (30 cm) in length, are known for their aggressive behavior and fearless attitude.

They inhabit the open coastlines at depths ranging from 10 to 240 feet (3 to 73 meters), where they fiercely defend their burrows from any potential intruders.

What makes the sarcastic fringehead truly unique is its oversized jaw, which can extend past its eyes and is lined with numerous needle-like teeth. This adaptation allows them to effectively intimidate and ward off predators or competitors.

Their elongated, slender bodies and long dorsal fins further contribute to their striking appearance.

2. Frilled Shark

OpenCage, CC BY-SA 2.5, via Wikimedia Commons

Often referred to as a “living fossil,” the frilled shark is a rare and unusual creature that belongs to its own order. These sharks are primarily found in the deep marine areas of Japan at depths of 200 to 4,200 feet (60 to 1,280 meters), but they have also been spotted in the Eastern Pacific, Eastern Atlantic, and Indian Oceans.

The Southern African Frilled Shark, a newly discovered species, inhabits the waters around Africa.

Unlike most sharks, the frilled shark has an eel-like body that typically grows to around 6.5 feet (2 meters) in length. Its most distinctive feature is the six pairs of gills covered by frill-like skin flaps, which give the shark its name.

With its ancient lineage and unique appearance, the frilled shark is a fascinating reminder of the ocean’s living history.

3. Giant Squid

Once believed to be mythical creatures, giant squids have captured the imagination of people for centuries. These colossal cephalopods inhabit the icy depths of 1,650 to 3,300 feet (500 to 1,000 meters) and can grow up to an impressive 43 feet (13 meters) in length, although some unverified reports suggest they may reach even greater sizes.

Giant squids are thought to have a worldwide distribution, with specimens washing up on the shores of New Zealand, Pacific Islands, and along the coasts of the Northern Atlantic Ocean and southern Africa.

Some researchers believe there may be up to eight different species of giant squid, while others argue for a single species (ref). Despite their size and widespread distribution, much about these elusive creatures remains a mystery.

4. Oarfish

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The oarfish, the largest known bony fish in the sea, is an incredibly long and slender creature that can grow up to 36 feet (11 meters) in length and weigh as much as 600 pounds (270 kilograms). These enigmatic fish prefer the depths of around 3,000 feet (914 meters) but have occasionally been known to venture closer to the surface.

In the past, these weird looking fish were believed to be the inspiration for ancient myths about powerful sea serpents. However, despite their intimidating size, oarfish are actually gentle giants with no visible teeth, feeding primarily on plankton.

Sightings of live oarfish are incredibly rare, with the first video footage of a live specimen captured by the US Navy in 2001 (ref).

5. Barreleye

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The Pacific barreleye fish is a true marvel of the deep sea, with its highly unique and transparent head that houses a pair of sensitive, barrel-like eyes topped with green, spherical lenses. These fascinating creatures were first discovered alive off the central coast of California at depths between 2,000 and 2,600 feet (600 to 800 meters).

Barreleyes have small mouths and are precise hunters, targeting small prey such as plankton and jellyfish. They are known to remain nearly motionless in the water, using their large, flat fins to maintain their position. When prey is spotted, they rotate their eyes, including their mouth in their field of view, to accurately strike.

The first intact specimen with its soft, transparent head was found by the Monterey Bay Aquarium Research Institute in 2009 (ref).

6. Chimaera

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Discovered at depths of around 4,200 feet (1,280 meters), the chimaera appears to be a patchwork of various fish parts. These ancient fish have skeletons made of hardened cartilage instead of bones and are equipped with sensory organs on either side of their head that detect electrical fields in the water to locate prey.

Chimaeras, also known as ratfish, rabbitfish, or ghost sharks, are considered one of the oldest fish species, with their lineage diverging from sharks around 400 million years ago. They have remained largely unchanged since the time of the dinosaurs.

Most chimaeras possess mildly venomous spines along their backs, adding to their unique and somewhat eerie appearance.

7. Zombie Worms (Osedax)

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Despite their nickname, zombie worms, or Osedax, don’t actually crave brains or come back from the dead. Instead, these small worms, measuring 1 to 3 inches (2 to 7 centimeters) in length, earned their moniker due to their peculiar habit of seeking out and devouring bones.

They were first discovered at depths of around 10,000 feet (3,000 meters), feasting on the decaying bones of a gray whale (ref).

Zombie worms secrete an acid from their skin that dissolves the bone, exposing the protein and fat within. However, these worms lack a mouth or stomach of their own. Instead, they rely on symbiotic bacteria living inside them to digest the protein and fat, which is then distributed to the worm host through a currently unknown mechanism.

8. Giant Isopod

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Although it may resemble a creature from another world, the giant isopod is a denizen of the deep sea, found at depths ranging from 550 to 7,020 feet (170 to 2,140 meters). These massive crustaceans are the largest members of the isopod family, typically growing to lengths of 12 to 16 inches (30 to 40 centimeters).

As carnivorous scavengers, giant isopods traverse the deep sea floor where light is scarce, using their large antennae to feel for any available food sources. They consume a variety of items, including the decaying remains of other marine life and slow-moving creatures such as sea cucumbers and sponges.

Their ability to thrive in the extreme conditions of the deep sea is a testament to their adaptability.

9. Tardigrades

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Tardigrades, also known as water bears, are microscopic animals with an incredible ability to survive in the most extreme conditions imaginable. With around 800 known species worldwide, these tiny creatures can withstand the vacuum of space, pressures up to 600 times that of normal atmospheric pressure, and temperatures as low as -272°C (-458°F) or as high as 150°C (302°F).

These resilient animals can survive in rooms filled with helium gas and have even been revived after being suspended in liquid air at -190°C (-310°F) for 21 months. When tardigrades finally succumb to death, their bodies encase themselves in a glass-like substance, further adding to their mystique.

Their extraordinary adaptability and survival skills make them one of the most fascinating creatures on Earth.

10. Bobbit Worm

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Resembling a terrifying Sarlacc pit from the Star Wars universe, the bobbit worm is a formidable predator that can grow up to 10 feet (3 meters) in length. These worms bury themselves in the loose sediment of the ocean floor at depths of 30 to 150 feet (10 to 45 meters), lying in wait for unsuspecting prey to swim or crawl by.

They are commonly found in the warm waters surrounding the Indo-Pacific region.

The bobbit worm is covered in bristles that can cause permanent nerve damage, so it’s best to admire them from a safe distance. With their incredible speed and sharp teeth, these worms are capable of slicing fish in half with a single strike and can even chew through coral reefs.

Their nightmarish appearance and impressive hunting abilities make them one of the most fearsome creatures lurking in the depths of the ocean.

Exploring the Bizarre

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From the sarcastic fringehead to the bobbit worm, the deep sea is home to an astounding array of creepy and captivating creatures. These 10 animals showcase the incredible diversity and adaptability of life in the ocean’s darkest depths.

As we continue to explore the vast expanse of the deep sea, there is no doubt that we will uncover even more bizarre and fascinating species that challenge our understanding of life on Earth.

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Davin is a jack-of-all-trades but has professional training and experience in various home and garden subjects. He leans on other experts when needed and edits and fact-checks all articles.