Tradition / Region: Icelandic Mythology
Alternative Name: –
Category: Whale, Cow

The Myth

The Nauthveli, also called the Ox-Whale, is one of Iceland’s feared illhveli (“evil whales”) and is said to be the second largest of these monstrous sea creatures. Like the other evil whales, it is considered inedible, and tradition warns that merely speaking its name aloud can summon it.

The Nauthveli is a massive toothed whale with a black-and-white body resembling a cow. Its enormous head resembles that of a bull, bearing two large nodules, while its long body narrows into a worm-like tail without fins.

Its most terrifying feature is its voice. When hungry, the Nauthveli lets out an immense bull-like bellow that echoes across the sea and coastline. The sound resembles the roar of enraged cattle and can be heard over great distances. Its vibrations shake the ground and are powerful enough to knock oars from sailors’ hands. Whenever its bellow is heard, people refuse to sail.

Like all evil whales, the Nauthveli attacks boats and delights in killing people, but it has a particular craving for cattle. Its supernatural bellow hypnotizes cows and bulls, compelling them to run over cliffs and plunge into the sea. Once they reach the water, the whale toys with them like a cat playing with a mouse before biting them in half and devouring them.

The creature is also drawn to cattle carried aboard ships. One legend tells of a Nauthveli that relentlessly pursued a vessel near Grímsey until the sailors released the single cow they were transporting. The animal immediately leapt into the sea, satisfying the monster.

After the Nauthveli has been heard, cattle are traditionally kept locked away for several days until its enchantment fades. In areas where the monster was believed to roam, herding cattle near the coast was discouraged. According to tradition, sacrificing a single bull or cow would appease the Nauthveli, making the sea safe once more.

Sources

Wikipedia contributors. (n.d.). Fylgja. In Wikipedia. Retrieved June 29, 2026, from https://en.wikipedia.org/wiki/Fylgja

Tradition / Region: Japanese Mythology
Alternate Names: Monster Whale Curse
Category: Whale, Ghost

The Myth

During his years working as a kamishibai artist, Mizuki Shigeru once created a paper-theater story called Monster Whale. The tale told of a man who ate nothing but whale meat. Over time, his body began to change, and he slowly came to resemble a whale himself. As the story neared its end, the man was struck by a severe fever. Even after consulting a doctor, no cause for the illness could be found.

While performing this story repeatedly, Mizuki himself fell ill with an unexplained fever. Medical treatment brought no answers, and the sickness lingered. Eventually, he decided to stop performing Monster Whale. Soon after, his fever disappeared as suddenly as it had come.

Mizuki laughed it off at the time, calling it the curse of the monster whale. Yet as years passed, he reconsidered the experience. He came to feel that the story may have touched on something unseen, something that did not reveal itself openly. As the tale of the monster whale concludes in his later writings, collected in works such as Nihon Yokai Taizen, it leaves a quiet warning: though nothing may seem to be happening, there is always something mysterious moving just beyond human sight.

Sources

TYZ Yokai Blog contributors. (n.d.). Bake-kujira (鯨骨霊 / バクジラ). In TYZ Yokai Blog, from https://tyz-yokai.blog.jp/archives/1077754091.html