The Lair of Leviathan: 15 Incredible Deep Ocean Creatures That Look Like Aliens

Space is not the only place fraught with many mysteries and dangers. Literally under our feet lies an equally mysterious and dangerous world, so different from ours that its inhabitants could well become space fiction or horror alien movie characters. We are talking about the ocean, the depths of which ancient people called the kingdom of Leviathan, the biblical giant multi-headed sea serpent that terrifies sailors with its name alone. Leviathan was a fictional deep sea monster, but modern science tells us that the real ones do exist.

Why do deep sea creatures look so exotic, sometimes even disgusting and frightening, and can they really be aliens who settled on Earth thousands of years ago?

In this article, you will find answers to these questions and get acquainted with the TOP 15 deep ocean animals, the biology of which will blow your mind. From cute and harmless plankton eaters to terrifying and cruel predators, these representatives of marine fauna remind us that exploring the ocean is one of the ways to learn the evolutional secrets of biological forms not only on Earth but also on other planets.

So, get ready to discover the incredible world of weird deep sea creatures with Orbital Today as we dive into Leviathan’s lair.

Why Do Ocean Animals Look Like Aliens?

The extraordinary and sometimes fantastic appearance of deep ocean creatures is due to the evolutionary adaptations they have developed to survive in the extreme conditions of their habitat.

Lack of light

Most deep sea zones start at depths of 200 meters and lower, where little light penetrates. Because of this, deep ocean animals are either completely blind or have uniquely developed, i.e., telescopic eyes for perceiving weak light. Many of them also have the ability for bioluminescence, which allows them to attract prey or use light as camouflage against sea predators.

High Pressure And Low Temperature

At depth, cold and low pressure prevail, which often leads to the appearance of unusual deep  sea creature body shapes, such as gelatinous or flattened structures with long limbs or other organs that allow them to move more efficiently in the water or along the bottom, obtain food, or camouflage themselves.

Little Food

Food is limited at great depths, so many deep ocean creatures are either detritivores that feed on marine snow, organic debris falling from above, or predators capable of capturing rare prey with massive jaws or other means, such as releasing toxins that paralyse the prey.

These adaptations make deep ocean animals look like creatures from science fiction, but they are actually the result of millions of years of evolution, allowing them to survive in one of the most inhospitable environments on Earth.

TOP 15 Weirdest Deep Sea Creatures According to Orbital Today

Today, science knows about 235,000 marine species, but researchers say that this is only a tenth of all existing marine fauna. Just think about how rich and diverse the underwater world is and how much we still have to learn. In the meantime, as scientists continue their research, we have handpicked the TOP 15 weirdest deep sea creatures: from cute to ugly species.

Alien Looking Jellyfish

Jellyfish are the most ancient deep ocean creatures, the origin of which, according to some scientists, can go back 700 million years, which is about three times the age of the first dinosaurs! Perhaps, they are those aliens? Let’s try to imagine this by studying some of the most exotic species of jellyfish.

The Lion’s Mane Jellyfish (Cyanea Capillata)

The lion’s mane jellyfish is named for the huge number of long, hair-like tentacles that extend from the bottom of its bell-shaped body and resemble a mane. Just as the lion is the king of animals, Cyanea Capillata is the king of jellyfish. This is one of the largest species of deep sea creatures of the invertebrate class in the world; its largest individuals reach a length of 6.5 feet, and the largest one discovered was 120 feet long, which is longer than a blue whale!!!

This alien looking jellyfish uses its tentacles to catch and eat prey such as fish, zooplankton, and smaller jellyfish. It tightly envelops its prey with tentacles and stuns them with nematocysts containing poison. The lion’s mane jellyfish also has bioluminescent abilities, meaning it can produce its own light and glow in the dark underwater.

These jelly giants live in the cold waters of the Arctic, North Atlantic, and North Pacific oceans at depths of up to 80 feet.

The Predatory Tunicate (Megalodicopia Hians) 

The Predatory Tunicate is named so for its unique body shape and feeding method. If you’ve ever seen a Venus flytrap capture an insect, you have a clue as to how a predatory tunicate eats. Its mouth, in the form of a large hood, quickly slams shut when a small animal, such as a crustacean or small fish, gets inside and does not open until it is ready to eat again.

The body of this slug measures about 13 cm across, and these creatures live at depths of up to 3,300 feet in the Monterrey Canyons area off the California coast. This alien looking jellyfish is also unique because it is a hermaphrodite that can self-reproduce when there are no other species nearby.

Giant Phantom Jellyfish (Stygiomedusa Gigantea)

Perhaps, design creators were inspired by the appearance of this jellyfish. After all, it looks like alien spaceships with thick ribbons flowing from below. However, this is not why the Giant Phantom jellyfish got its name. Its bell body of spongy tissue reaches 4 feet in diameter, and its tentacles are 30 feet long. It is extremely rare to encounter this species; over the past hundred years, only one hundred such cases have been recorded. This is because this alien looking jellyfish prefers to swim very deep, at 3300 feet or lower, but sometimes these creatures can rise to 300 – 1000 feet when carried by underwater currents.

Stygiomedusa gigantea uses its four ribbon arms not only for moving but also for eating. The arms capture their prey, usually plankton and small fish, and put them in their mouths. This alien creature lives in the Southern Ocean, near places such as the USA, Spain, Africa, India, and New Zealand.

Alien Fish

The term “alien fish” unites marine animals that look like aliens, but inherit the characteristic features of fish. This is a very large group of species, but we will focus on the most exotic creatures — not only because of their appearance, but also the characteristics of their existence.

Anglerfish (Lophiiformes) 

The anglerfish gets its name from the special fin that grows from its head and resembles a fishing rod. At the end of the rod is an esca, a sac-shaped organ containing bioluminescent bacteria that glows brightly in the dark, attracting prey: small fish and crustacean mollusks.

There are over 200 species of deep-sea anglerfish in a variety of shapes and sizes, from the recognisable toothy jaws of the black seadevil to the bottom-dwelling sea toad called coffinfish. This alien looking fish reaches up to 4 feet in length; however, this only applies to females.

Male anglerfish are typically tiny, with simplified body features, and live as parasites on the female’s body, eventually physically merging with the female and sharing a circulatory system. This process is called sexual parasitism and allows males to obtain nutrients from females while simultaneously impregnating them for reproduction.

Depending on the species, anglerfish live in the Pacific and Atlantic oceans at depths ranging from 100 to 3,000 feet.

Barreleye Fish (Macropinna Microstoma)

The barreleye fish has unique features, such as a transparent head shield that protects its rotating tube-shaped eyes, which are usually directed upward or forward to detect the silhouettes of available prey. Although the eyes appear green, the lenses are actually coloured with a yellow pigment that helps the barreleyes distinguish between sunlight and bioluminescence, making these fish impossible to fool with conventional deep sea camouflage tactics. Also, these creatures may have reflective soles serving as camouflage in the form of counter-lighting from larger predators.

The dark spots previously thought to be eyes are actually the fish’s olfactory organs, or nostrils. Its narrow, small mouth requires precise direction to capture prey because the barrel eye measures no more than half a foot. This alien looking fish feeds on zooplankton and small crustaceans and lives at a depth of 2000-2500 feet in the Northern Pacific Ocean.

Dragonfish (Grammatostomias flagellibarba) 

The dragonfish, or Grammatostomias Flagellibarba, is one of the extremely ugly sea animals. Despite its modest size of 6 inches, it has massive transparent teeth that are stronger than those of a piranha. This alien fish is distinguished by its dark colour, allowing it to blend into the darkness of the depths, and a long chin barbel that significantly exceeds the length of its body. It also has photophores behind its eyes and along its sides that produce light signals unique to each species. The dragonfish uses these signals and its barbel to attract smaller fish and crustaceans, to attack them with its powerful, sharp jaws. This small predatory monster lives in the northern and western Atlantic Ocean and in the Gulf of Mexico at a depth of about 5,000 feet.

Deep-Sea Hatchetfish (Sternoptychidae)

Hatchetfish is named this way for its unique body shape, reminiscent of an ax blade. This small fish, measuring no more than three inches, lives in temperate and tropical seas around the world at depths of 1300-4100 feet and feeds on small crustaceans and animal plankton. To search for food, the hatchetfish’s eyes can focus at both close and far distances. When potential prey gets close enough, the hatchetfish quickly attacks, using its sharp teeth to grab the prey. When it is threatened, the hatchetfish uses photophores. This alien looking fish creates counter-lighting, helping it camouflage itself from predators and blend into the background of its environment.

The Blobfish (Psychrolutes Marcidus) 

The blobfish was named for its drop-shaped shape and sluggish, sad face. Indeed, on land, it appears as a pale, pink, jelly-like mass with a drooping mouth and a large nose, which, in 2013, earned it the title of “world’s ugliest animal”. However, in its natural habitat, at depths of 2,000 to 4,000 feet, this alien looking fish looks like an ordinary fish with a thick head, large jaws, and feathery pectoral fins.

This transformation is due to the huge difference in pressure between its natural habitat and surface conditions. The blobfish does not have strong bones or muscles, but its density is slightly less than that of seawater, allowing it to swim above the very bottom without expending energy. However, if you lift a blobfish to the surface, where the pressure is much lower, its body becomes limp and jelly-like.

The main food source for blobfish is crustaceans. Due to the lack of developed muscles, it does not hunt for prey but simply waits for molluscs to swim nearby where the blobfish captures them with its mouth.

Blobfish size ranges from 12 to 28 inches, while its weight can reach up to 10 kg. These ugly sea animals live in the waters off the coast of Australia, Tasmania, and New Zealand.

Stonefish (Synanceia Verrucosa) 

Stonefish are called so because they have warts and growths all over their bodies allowing them to camouflage themselves in their environment. This fish often looks like a crusty rock or piece of coral. Stonefish typically live on the coral floor, often under rocks or ledges up to 20m deep, but can also burrow into the sand using their large pectoral fins. The species is widely distributed in tropical and marine waters of the Indo-Pacific region.

Despite its small size of up to 15 inches, the stonefish is a dangerous predator of small fish and crustaceans. The fish quietly waits for prey and then quickly grabs it with its retractable jaw, just like the well-known Alien in water. This happens so quickly that you will need a camera with a fast shutter speed to capture this moment. But if you want to attack this alien looking fish, you may regret this. The thing is, stonefish are the most poisonous fish in the world. It has thirteen thick spines in its dorsal fin that can inject highly toxic venom similar in potency to that of a cobra.

Many people died from stonefish stings until an antidote was developed in Melbourne in 1959. However, people still suffer from these injections, and the recovery process can take months.

Alien Looking Squid

Squids are another representative of deep sea creatures that can look so creepy that even the most ugly alien looking fish will seem cute in comparison. You’ll see that for yourself now.

Giant Squid (Architeuthis Dux) 

Giant squid. Credit:.livescience.com

Giant Squids are often called “deep sea monsters”. They are the largest of all living cephalopods and the largest individual invertebrates in the world. They can measure up to 69 feet in length and weigh up to 2000 pounds!!! Giant squids have a mantle, 8 regular tentacles, and two long trapping tentacles that are used to capture prey. The inside of the tentacles is covered with hundreds of suckers with sharp chitin rings. These descendants of Leviathan live at depths of up to 2,500 feet, in cold waters near continental shelves and underwater ridges.

Giant alien looking squids feed on deep-sea fish that glow in the dark. They catch prey with their tentacles and bring it to the radula (toothed tongue) to grind it. Despite their size, giant squids have a dangerous opponent. This is a sperm whale. Round scars from the giant squid suckers were repeatedly found on sperm whale bodies, and squid remains were found in whale stomachs, indicating that collisions between these two sea giants generally do not end in the squids’ favour.

Vampire Squid (Vampyroteuthis Infernalis)

Scientists named this animal Vampyroteuthis Infernalis, which is Latin for “vampire squid from hell.” But this name is deceptive — it is not a squid or an octopus at all. In the 1940s and 1950s, scientists determined that it was a one-of-a-kind species of mollusc in the family Vampyroteuthidae.

The vampire squid measures no more than 12 inches in size and lives at depths of 1,000 to 3,000 feet, primarily in very low-oxygen zones in temperate and tropical waters around the world. Such extreme conditions force the animal to eat poorly — zooplankton, mucus, excrement, and marine snow.

One of the most striking features of this deep sea animal is its blue eyes, which have the largest proportions in the animal kingdom. It also has two thin tentacles that can be up to eight times the length of its body. Each tentacle has tiny hairs and sensory nerves that help it sense its environment and, possibly, detect food.

At times of danger, the vampire squid unfolds its webbed hands, wraps them around its mantle like a cloak, and throws out a luminous cloud of mucus to distract predators. But even if the predator has found its prey, this alien looking squid has a high chance of surviving. If the upper part of its arm is broken or bitten off, the squid will be able to recover.

The Glass Squid (Teuthowenia Pellucida)

The glass squid got the name for its transparent body with bluish luminescence, which makes it almost invisible at depth. Its only visible internal organ is a digestive gland, similar to the chordate’s liver. The animal has eight short tentacles with a longer pair at the end of its swollen body. Another characteristic feature, unnaturally bulging eyes, is an adaptation that allows it to better gather light, which is critical for survival in deep conditions.

Glass squid are very small, measuring no more than eight inches for mature females, which are always larger than males. This squid that looks like alien feeds on fish eggs and invertebrates. To scare away predators, usually deep-sea fish, the animal sharply inflates or, on the contrary, curls up into a ball, like a sea urchin. If this does not work, the squid uses a reactive impulse — it throws out a stream of water to quickly move through the water column.

Glass squids are primarily found in the South Pacific Ocean, at depths ranging from 3,000 to 5,200 feet. Even though they are the main food of deep-sea fish, they are not in danger of extinction. Glass squids reproduce very actively. One female can lay up to 700 eggs at a time, from which young species hatch and mature very quickly.

What Shark Looks Like an Alien?

There are none, you may say, but you will be wrong. There are about 500 species of sharks living in the ocean, and the sharks that we’re used to seeing in movies or underwater zoos live in shallow waters. In the depths live ugly monsters that could very well be aliens.

Goblin Shark (Mitsukurina Owstoni)

The goblin shark gets its name from its spatulate snout, flabby body, and tail with an underdeveloped lower blade. One of its distinguishing features is its prominent mouth. The mouth may retract under the eye or extend forward under the muzzle. The lower part of the muzzle is highly porous. These pores are the external openings of the ampullae of Lorenzini, organs that detect electricity. The goblin shark most likely hunts by detecting electrical fields. When feeding, the goblin shark extends its jaws forward faster than any other shark species. Its most often prey are bony fish, squid, and crustaceans. Even though adult goblin specimens can reach a length of 13 feet, this alien looking fish is fortunately not a danger to humans, as it lives at a depth of about 3000-4000 feet.

Basking Shark (Cetorhinus Maximus)

This shark was nicknamed the sea monster, and ancient sailors feared this was exactly what these giant creatures from the depths were. Cetorhinus maximus is the second largest fish in the sea, after the tiger shark. It can reach lengths of up to 40 feet and weigh up to 4 tonnes. Despite its size and intimidating huge mouth with hundreds of small sharp teeth, the basking shark is a harmless plankton eater, and its large mouth is only necessary to filter 2,000 tonnes of seawater per hour through its complex gills, catching the plankton in the quantities it requires.

Basking sharks are migratory species found in cool to warm temperate waters of all oceans at depths of up to 3,000 feet. Unfortunately, these coolest sea creatures are gradually becoming extinct. The irony is that basking sharks are not predators for people, but people are predators for them.

Historically, the basking shark was hunted for its liver oil, which was used to produce vitamin A, lamp oil, and tanned leather. Liver fat is also rich in squalene, which is used in medicine and cosmetology. These sharks were also killed for their giant fins, which were in great demand in Asian markets. The species is now protected throughout much of its range, particularly in the UK, US, EU, and parts of New Zealand.

What’s the Most Alien-Looking Animal?

As you can see, there are many deep ocean animals that look like aliens, but we believe that the main alien in the ocean title belongs to Phronima Sedentaria, a crustacean from the order Amphipoda of the Phronimidae family.

It is a tiny parasitoid that lives up to 3,300 deep in oceans. Females of Phronima Sedentaria can reach up to 42 mm in length, while males are usually smaller, at around 15 mm. Phronima Sedentaria has a complex optical system with two sets of compound eyes, one pointing downwards and the other pointing upwards.

As befits any parasite, Phronima lives at the expense of other creatures. These are salpas – gelatinous, barrel-shaped zooplankton. Equipped with impressive front claws, Phronima attacks salpas and carves out their innards, leaving an empty barrel-shaped structure. Then, it climbs inside and uses the salpa’s jelly-like shell as a home to lay eggs in it. For this, Phronima was nicknamed a monster in a barrel. And we consider it the most cruel and disgusting of all known deep sea creatures.

Is a Phronima an Alien?

This may well be the case. According to one legend, Phronima served as inspiration for the creation of the parasitic xenomorph in the Alien movie. We can’t verify this, but look at how similar they are.

Should we look deeper?

Scientists sometimes joke that we know the sea depths worse than the planets in the solar system. To a certain extent, this is true: today, according to various sources, only 3-5% of the World Ocean has been explored. But should we look deeper? Who knows what other deep sea creatures await us in Leviathan’s lair and how they will behave when they learn about our existence?

 References and Additional Information:

• Animals of the deep
  https://www.mbari.org/education/animals-of-the-deep/
• The deep sea
  https://neal.fun/deep-sea/
• Ocean life
  https://ocean.si.edu/ocean-life
• Meet Phronima, the barrel-riding parasite that inspired the movie Alien https://theconversation.com/meet-phronima-the-barrel-riding-parasite-that-inspired-the-movie-alien-22555
• Why do deep sea animals look so weird
  https://www.montereybayaquarium.org/stories/deep-sea-animal-adaptations
• Animals by Scientific Class Names 
  https://a-z-animals.com/animals/class/