The ocean, seas, and other deep bodies of water are said to hold vast amounts of creatures. Some of these bodies of water are largely unfathomable and remain untouched by humans.

To understand the ocean and what lies beneath, ancient civilizations created mythical sea creatures in an attempt to explain some of the unexplainable phenomena happening in and around these large bodies of water.

Many of the myths and superstitions connected to these mythical sea creatures have existed for centuries, if not millenniums.

Because the Earth is covered by roughly 2/3 of water, some have said that the ocean holds many secrets.

At times the weather is unpredictable and many a sailor has lost their life to the strength of the sea.

Even inland lakes and some rivers can be lethal leaving some to perish as a result of the water's unpredictable fury.

In light of the mystery of these bodies of water, what follows is a snapshot of 50 of the most well-known mythical sea creatures.

Top 50 Mythical Sea Creature List:

1. The Loch Ness Monster

The Loch Ness monster is a mythical sea creature believed to be living in the Scottish Loch (Lake) Ness in the Scottish highlands. It is said to be very large with a long neck and one or more humps on its back.

Although there have been as many as 1,000 sightings of "Nessie" most have been disproved and many scholars have concluded that the sea monster is only a psychological figment of peoples' imaginations.

2. The Kraken

The Kraken is one of the more well-known and most terrifying of all mythical sea creatures.

Most scholars believe that sailors who encountered giant squid living off the coast of Norway and Greenland most likely spun their likeness into a monster, and named it the Kraken.

The Kraken is said to be so fierce and terrorizing that it has become a legend many times over due to its gigantic, intimidating size.

3. Mermaids

A mermaid is a famous mythical sea creature that is half woman and half fish or sea serpent. Mermaids can be enchanting but are typically dangerous to sailors and seamen. They can be blamed for such events as floods, storms, shipwrecks, and drownings at sea. Rule of thumb, if you see a mermaid, avoid them!

4. Scylla

In Greek mythology, Scylla is a mythical sea creature who inhabits one side of a narrow of water opposite her cohort Charybdis. Any sailor or sailing vessel that enters the narrow channel called the Strait of Messina has to get by Scylla on one side and Charybdis on the other. Most sailors are terrified of her and avoid the channel altogether.

5. Charybdis

In Greek mythology, Charybdis along with Scylla, another fallen sea nymph turned sea monster, is a feared mythical sea creature who patrols the Strait of Messina. Together with Scylla, Charybdis terrorizes sailors and other Greek heroes including Odysseus, Jason, and Aeneas.

6. Nereus

In Greek mythology, Nereus is a mythical sea creature who lives at the bottom of the Aegean Sea. He is the father of 50 nereids, and he is said to be a God who never lies and in whom one can trust. Sometimes referred to as "the old man and the sea", Nereus is a god whose empire lies in the Aegean Sea.

7. Triton

According to Greek mythology, Triton is a mythical sea creature who is the son of Poseidon. Triton is half man, half fish, and lives below the sea in a palace.

8. Gunakadeit

Gunakadeit is a legendary human turned sea wolf/sea monster. According to a Tlingit myth, Gunakadeit was walking along the shore, saw a monster, killed it, skinned it, and donned the creature's skin. He then went into the sea and delivered salmon to the hungry villagers, thereby symbolizing the arrival of prosperity and good luck.

9. The Dobnar-chu

The mythical sea creature named The Dobnar-Chu is a part of Irish folklore believed to be living in the deep lakes of Ireland. This creature is said to be half dog or otter and half fish. He is also aggressively carnivorous and will attack both humans and dogs.

10. The Sirens

The sirens were a group of female mythical sea creatures who lured sailors to shipwreck on rocks with their singing. Odysseus was believed to have discovered the legendary Sirens on his return trip home from Troy.

11. Oceanids

The Oceanids were a collective family of 3,000 water goddesses who rule over the Earth's freshwater. These mythical sea creatures are derived from Greek mythology and are believed to be nymphs whose primary occupation was to monitor the rain clouds, springs, and fountains of the Earth.

12. Mermen

Mermen are the male mythical sea creature counterpart to the mermaid. They are men from the waist up and fish from the waist down. They range from hideous in some folklore accounts to handsome in others.

13. Nereid

Nereid is the collective daughter of Nereus and Oceanid Doris in Greek Mythology. Dubbed the old man and the sea, Nereus is the father of 50 nereid female nymphs. These beautiful, gentle nymphs symbolize everything good and wonderful about the ocean.

14. The Aspidochleone

According to Greek mythology, the Aspidochleone is a fabled sea turtle with an island on its back, complete with dunes, greenery, and trees. The Greek translation of asp-turtle means a dangerous mythical sea creature that allegedly kills sailors and destroys their ships.

15. Jormungandr

In Norse mythology, Jormungandr is a "huge monster" from the sea who is so big he can surround the earth and grab his tail. In Marvel Comics, Jormungandr is known as the Midgard Serpent. Thor, the thunder god, is the arch-enemy of Jormungandr.

16. The Kappa

The Kappa is an amphibious demon or imp from traditional Japanese folklore. This mythical sea creature is green with webbed feet and hands and a turtle-like shell on its back. The Kappa is usually depicted as half humanoid and half reptile, and legend has it that it is extremely intelligent and cunning.

17. Lernean Hydra

Residing in Lake Lerna, the Lernean Hydra is a mythical sea creature from both Greek and Roman mythology that has several heads. It was believed that Lerna was the entrance to the underworld due to the presence of the Lernean Hydra who spent a lot of time terrorizing the countryside around Lake Lerna.

18. Umibozu

The Umibozu is a sea spirit from Japanese mythology who resides in the ocean. He emerges on a calm sea that suddenly turns stormy and sinks ships and drowns sailors. You don't need to do much to antagonize Umibozu. If you speak to him the result is the capsizing of the ship and the death of many sailors. 

19. Leviathan

Leviathan is a biblical name for an ancient Jewish mythical sea creature. Mentioned several times in the bible, Leviathan has been interpreted by late 19th century scholars to be either a great whale or a large crocodile.

20. The Biesht Kione

In Irish folklore, there is a mythical sea creature known as the Biesht Kione, or "Beast with the Black Head". Located in the Irish Sea near the Isle of Man, the Biesht Kione made its home in the deepest part of the ocean. Terrified sailors would often tell of seeing its large blackhead rise above the waters.

21. The Cthulhu

The Cthulhu is a fictional figment of the imagination made popular by H.P. Lovecraft and first published in 1928. In his essays, Lovecraft writes of Cththlu a priest or leader of the Old Ones, a species who came to Earth before humans who have since slipped under the crust of the Earth into the Pacific Ocean.

22. Lusca

Lusca is a giant sea monster living in the Blue Hole near the island of Andros in the Bahamas This mythical sea creature is said to be enormous, resembling a giant octopus or giant squid and allegedly measuring a whopping 75 feet in length.

23. Vodyanoy

The Vodyanoy is a male water spirit living at the bottom of the Great Sea. According to Slavic mythology, Vodyanoy is an evil spirit who delights in drowning humans, so beware!

24. CadBorosaurus

British Columbia on the North American Pacific Coast is home to a mythical sea creature by the name of Cadborosaurus. He is an alleged sea monster closely resembling a lizard or reptile, whose nickname is "Caddy". There have been at least 300 sightings of "Caddy" in the last 80 years.

25. Bakunawa

Bakunawa is a serpent-like dragon from Philippine mythology. This mythical sea creature is quite gigantic and is believed to be the cause of eclipses, earthquakes, rains, and wind. Bakuwana is a sea serpent but is also capable of inhabiting both the sky and the underworld.

26. Calypso

In Greek mythology, Calypso is a nymph living on the island of Ogygia. This mythical sea creature has special powers and was believed to have detained Odysseus for 7 years according to Homer's Odyssey. Thus, in Greek, the definition of calypso is "she who hides".

27. Cetus

In Greek mythology, The Cetus was a deadly sea monster pursued by both Perseus and Heracles. The Cetus constellation, "whale" is located near other water-related constellations such as Aquarius, Pisces, and Eridanus.

28. Akkorokamui

Like a mythical sea creature from Japanese folklore, the Akkorkamui is a gigantic octopus. He is believed to reside in the waters off of Funka Bay and is said to be about 390 feet long. He is entirely red in appearance and is big enough to swallow whole boats and whales In one big gulp. He is also known to frequent the nearby waters of Taiwan and Korea.

29. Kaijin

Kaijin is a mythical sea creature, also from Japan, who is mentioned quite often in books from the Edo period. He had some human traits, such as eyebrows and skin around the waist, but Kaijin never spoke and could not live more than a few days out of the sea.

30. Selma

From Norweigan folklore, there emerges yet another sea/lake monster who goes by the name of Selma. Said to live in Lake Seljord in Norway, this mythical sea creature is alleged to have been sighted numerous times since the 1750's. Many say that it resembles a long anaconda-like snake, and a reptilian monster with a head like a horse.

31. Mussie

Mussie is a local name for a mythical sea creature thought to be living in Muskrat Lake, Ontario, Canada for quite some time. As legend would have it, Mussie is said to be around 24' long, with 3 ears and 3 eyes, closely resembling either a walrus, a sturgeon, or a 3 eyed Loch Ness monster. Mussies' diet on Muskrat lake reportedly consists of cattails!

32. The Cirein-Croin

The Cirein-Croin or Ceirean, is a mythical sea creature from Scottish/Gaelic folklore. The Cirein-Croin is a very large sea monster who has also been described as a dinosaur. He is so feared that legend tells that only the devil himself could kill The Cirein-Croin. Because he can swallow 7 whales and then disguise himself as a small silverfish when encountered, he is the 2nd scariest mythical sea creature on record.

33. FinFolk

A very mysterious type of mythical sea creature is known as the Finfolk, from Scottish/Celtic folklore. They live in Finfolkaheem, which is an underwater abode for half the year, and then go ashore to Hildaland during the spring and summer months. This all takes place in the Orkney Islands, a chain of islands in Northern Scotland. The Finfolk is said to be a race of creatures who delight in the abduction of humans for slavery purposes.

34. Grindylow

The Grindylow is a type of mythical sea creature from English folklore, most notably in the counties of Yorkshire and Lancastershire. They are believed to live in shallow waters such as rivers, lakes, coastal regions, and coral reefs. These creatures are said to be dangerous because they are a type of water spirit that grabs little children from the shore and drowns them.

35. Jengu

Among the African Sawa ethnic groups of Cameroon, a type of mythical sea creature named Jengu is believed to exist. Jengu is a water spirit, most notably a mermaid or merman of African descent who is very beautiful. The Jengu is also believed to be closely related to another African water spirit, the Mami Wata.

36. Mami Wata

Mami Wata is an African water spirit, thought to be a very beautiful but dangerous mythical sea creature. Originating in West, Central, and Southern Africa, Mami Wata is a goddess who is said to be a mermaid as well as a snake charmer and is believed to have "overseas" ancestry. Mami Wata has been in existence in Africa since before the invasion of Europeans in the 19th Century.

37. Qalupalik

The Qalupalik is a race of mythical sea creatures from Intuit mythology and legend. According to this legend, the Qalupalik is human-like and is considered ugly and evil with green skin, long hair, and claws. In addition, the Qalupalik wears an Amanti, a kind of parka with a pouch on her back for babies.

38. Kelpie

According to Scottish folklore, Kelpie, or water Kelpie, is a spirit who can change his form and who lives in certain lakes in Scotland. Descriptions of the mythical sea creature named Kelpie include a horse-like figure who can transform himself into a human, with one catch: he still has horse hooves. This has led writers in the day to associate Kelpie with the devil.

39. Rusalka

Rusalka is a Slavic term describing a female mythical sea creature, namely a mermaid, who is hostile in her dealings with humans. She is said to be either the soul of a child who died unbaptized or a virgin who drowned. She inhabits the Danube river and her counterparts allegedly live in parts of France and Germany. Beautiful and charming, Rusalka is also said to be vile and cunning.

40. Chessie

Chessie is the name given to a mythical sea creature turned ecological icon. As a staple of American folklore, Chessie is reportedly a sea monster living in the Chesapeake Bay. Since its alleged sighting in 1936, Chessie has become the subject of a 1986 coloring book depicting the need for protection of the ecology around the Bay.

41. Iku-Turso

Iku-Turso is an evil mythical sea creature from Finnish mythology. Iku-Turso is said to be the father of a disease, and the ox of Tuoni, who is the god of death.

42. Selkie

A selkie is a mythical sea creature or water spirit that can change from a seal to a human by shedding their skin, hence the name Selkie, or "seal folk". Selkies originated in Norse and Celtic mythology and are believed to reside in the Northern Islands of Scotland.

43. Bunyip

From the land down under, there is a mythical sea creature known as a bunyip. In Aboriginal Australia, the mythical sea creature named bunyip is translated to mean "devil or evil spirit". Allegedly the bunyip occupies swamps, lagoons, creeks, riverbeds, and waterholes all over the interior of Australia. The bunyip is also a tad bit moody, with moods ranging from ferocious predator to gentle herbivore.

44. Water Leaper

From Welsh mythology, we have a mythical sea creature named the Water Leaper. He is said to be a giant frog with a lizard tail and bat wings in place of his forelegs. He is an evil creature who makes his home in swamps and ponds and is believed to ambush any prey that comes close to the edge of the water where he is lurking.

45. Namazu

In Japanese mythology, a mythical sea creature by the name of Namazu is believed to be a giant catfish living under the Earth. He is guarded by the god Kashima who holds him down by using a stone. When Kashima lets up on the stone, Namazu is free to swim and thrash about, causing earthquakes.

46. Cipactli

From Aztec mythology, we have the Cipactli, a mythical sea creature that is part frog, part fish, and part crocodile. The Cipactli sea monster was living in primordial waters before the creation of the Earth. Two warriors teamed up and killed Cipactli and from his remains, the Earth was created.

47. Yacuruna

In Iquitos folklore, there is a god similar to Poseidon in Greek mythology. He is a mythical sea creature by the name of Yacuruna. It is believed that Yacuruna rides around the Amazon rainforest waters on a big black crocodile with a boa as a necklace. Fish and water reptiles are his subjects, and he is said to be quite attractive.

48. Hippocampus

Unlike the organ hippocampus in the human brain, there is a mythical sea creature from Phoenician and Greek mythology known as the Hippocampus. He has the lower body of a fish and the upper body of a horse, and he is said t0 have drawn the chariot of the god Poseidon.

49. The Fish-Man of Lierganes

According to the mythology of Cantabria located in the north of Spain, there exists a mythical sea creature known as the Fish-man of Lierganes. It has been noted that the Fish-Man looks like an amphibious, human being who has come to resemble a man who has been lost at sea for quite some time. 

50. Abaia

The Abaia is a huge, magical eel from Melanesian mythology that lives in the bottom of the freshwater lakes of Fiji, Solomon, and Vanuatu islands. This mythical sea creature is said to be very protective of the creatures living in the lake and if anyone tries to fish from the lake where the Abaia lives, they will encounter a tremendous wave resulting from the protective thrashing of the Abaia's tail.

Mythical sea creatures have existed since the beginning of time. Before the invention of sonar, radar, and satellites to explain the deep secrets of the sea, ancient civilizations from all over the world believed in the power of these mythical sea creatures.  This need for answers to the great mystery of the sea is an integral part of human history.