(host) Of all the many terrifying fae-like monsters haunting the waters of the world, the Nixie stands out. These half-human half-fish beings may at first glance look familiar, but they are much older and much scarier than the usual mermaid of pop culture. Thanks, Ariel. They love to shapeshift and sing mesmerizing melodies all while harboring an insatiable desire for humans which often veers into a dark obsession. So what is a Nixie? A water sprite, a nymph, a mermaid? Technically, yeah.

[adventurous music]

(Describer) A huge orange eye opens.

I'm Dr. Emily Zarka and this is "Monstrum."

(Describer) She wears mermaid hair.

The Nixie belongs to a large Germanic tradition of murderous shapeshifting water nymphs that also appear in folklore from Switzerland and Scandinavia. Known throughout folklore by many names, these deadly and enchanting water creatures may take the appearance of an old human with green teeth, green skin, and green hair. Most of the time, though, they take the form of a beautiful human covered with moss and seaweed and decorated with shells. Some German legends describe the Nixie with slit ears or fishtails when they're in the water. They have the ability to appear clothed on land but the water dripping from their garments gives away their true identity. Throwing stones into the water can irritate the Nixie who may create a storm in response. Yep. These water monsters control the weather. An additionally scary thing about the Nixie is that they can haunt any body of water. No well, stream, river, pond, lake or ocean is safe. They lure their victims with music, usually singing, or in some stories they imitate a crying child to draw someone near before seizing and pulling their prey below the surface. What they do with them from there varies. In many tales, the Nixie serve as a cautionary tale for children who are told to avoid the water so as not to be grabbed, implying that they will not return. In other stories, the monsters require an annual human sacrifice and they prefer children. Stories of the deadly Nixie usually end with death but there are also accounts of a more romantic persuasion. Sometimes they will transform into horses to carry their willing human lovers to their crystal palaces. Some of these monsters apparently have alluring underwater homes. So yes, these stories implied that the Nixie mate with humans. Though such romantic encounters are not encouraged in their society, said to be ruled by a malevolent water diety akin to Satan. Named Nick from the ancient Icelandic, he will kill any of the Nixie who dare to even talk to a human. Described as more of a classic mermaid or merman, Old Nick is the fishtailed father of all the Nixies. Over time, and in some regions, this water deity became watered down into the Nixies who borrow his name. Because of this etymological connection, the Nixie is associated with malice more often than many of their global counterparts. Before Nick, and therefore all Nixies, somewhere around 700 CE, the famous text Beowulf mentioned nickers, violent water monsters. Some folklore theorized that Nixies may have originated from ancient spiritual practices of river and water god worship that turned nefarious after the introduction of Christianity when water worship was discouraged. Still, whispers and legends of the monster persisted and became popular across the globe thanks to a few key books in the 19th century. In the German fairy tale "Undine" published in 1811, a Nixie, here called water sprite, appears on the doorstep of a couple whose daughter drowned earlier that day. Appearing as a young human girl dripping wet, she is taken in by the grieving parents. She's exquisitely beautiful with golden hair, but is also known to have supernatural powers like controlling water and the weather, and a fiery temperament. Eventually, Undine marries a knight, and overnight becomes a nicer, more accommodating person. She claims the change is due to her now possessing a soul. Apparently, as a water sprite she didn't have one and can only get one by marrying a human. Even after she reveals her true nature, including her people's great beauty and otherworldly singing voices, her husband seems okay with the whole thing, which granted doesn't seem all that bad considering. Her water sprite uncle, however, is not pleased with this intervening marriage and repeatedly attacks the couple and their company with waves, frightening apparitions, storms, and floods. Eventually, Undine is forced to return to the Nixie's underwater crystal kingdom after her husband accuses her of being a sorceress. Meanwhile, her former knight husband remarries his former love and the old couple's biological daughter, who in a strange twist, didn't drown after all. Due to the rules of the Nixie society, Undine must reappear on land and give her husband a killer kiss for his infidelity, drowning him with her tears. So we have a beautiful, kind Nixie who, yes, is forced to kill her husband but the tale is presented as a tragic love story. Oh, and this story, yeah, it helped inspire Han's Christian Anderson's "The Little Mermaid." The Nixie in the Brothers Grimm 1857 tale, "Nix of the Mill-Pond" lacks any redeeming qualities. A man who recently lost his fortune sees a beautiful woman rise from the waters of the river by his mill. He recognizes her as a Nixie straight off and even though he is frightened, he accepts a strange bargain from her. She promises to restore his wealth if he pays her, "The young thing which has just been born." The young thing turns out to be his firstborn son whom his wife has only just delivered. When he realizes the horror of what he has done, he raises the boy to fear the water. This works until his son is now a married man himself. One day after a hunt, without thinking, the son washes his hands in a pond. The Nixie seizes the opportunity. She slowly rises up from the water and with a big smile, wraps her arms around him, dragging him down into the water with her. His distraught wife goes to the local witch for help who advises a series of steps to bring him out. First, she combs her hair near the water where he was taken. It works, sort of. Her husband's head momentarily appears above the surface but quickly disappears under the water again. The next day, she plays a flute, and this time half of his body emerges. On the third day, she works a golden spinning wheel by the pond and her husband fully emerges. He begins to leave the water but not before a tidal wave suddenly rises up and starts heading towards them. The woman calls upon the witch with one last plea for help. And help she does, by turning the wife into a toad and the huntsman into a frog, enabling them to survive the torrent of water. Luckily, they revert back to their human forms, but unluckily, they are separated by the wave. They live separate lives for years until one day as fate would have it, they cross paths. They do not recognize one another, but become good friends. One day, the Huntsman plays an interesting flute song, the very same one his wife did besides the pond so many years before. They suddenly realize who each other is and fall back in love. These stories established the Nixie as both villains and victims and popularized the female Nixie over the male Nix. Nixies, along with other water nymphs and mermaids, appear often in 19th century fiction as folkloric femme fatales that reflect patriarchal society's fear of the increasingly-liberated woman and changing gender roles. Because literature emphasizes the beauty of the Nixie, they're often seen as projections of desire, largely through the male gaze, but others interpret them as feminist symbols of the power of women and nature, as allegories for death, or even as a reminder of the dangers of drowning. I think more broadly, these 19th-century Nixies gesture towards modernity, their tempting songs and offers of treasure akin to the siren pull of industrialization which, likewise, promises luxury and wealth but at a severe cost. According to folklore, the Nixie lacks maternal instinct, sensibility, and a soul. Having a fishtail, supernatural foresight, or the ability to shapeshift are at odds with the parts of them that are more human-like. But it's the human side that presents the most danger. The mouth that can tell the future or lure one to a watery death. Or the arms that pull their prey down below. It's the human qualities that allow them to slip into society unnoticed. A wolf among sheep, or rather, a shark among seals.

(Describer) In outtakes, she admires her long wavy hair on her phone.

Old Nick is the--

[whines] It went on my lip. I'm sorry.

[crew laughs]

Okay. That time it landed on me.

(Describer) Accessibility provided by the US Department of Education.