Glühenvolk

A Glühenvolk (GLOO-ən-fohlk; Germ. Glühen "glow" + Volk "people") is a alien-like Wesen that be appeared in.

History
They are a very ancient Wesen species whose roots can be traced back to Africa. In the past their magnificent skin was thought to have magical properties, and today is simply valued for its beauty. Consequently they have been hunted to near extinction, and are considered as such by most other Wesen. Due to their rarity and beauty, many Wesen consider seeing a Glühenvolk to be good luck. In modern times, sightings of Glühenvolk have led humans to believe in the existence of extraterrestrials.

Biology
When they woge, Glühenvolk gain bulbous heads with a barely visible nose and ears. Their mouths are filled with yellow peg-like fangs. Most notably, Glühenvolk gain bio-luminescent skin that glows a gentle, yet brilliant electric blue. The bioluminescence of these creatures is caused by luciferase, a class of enzymes found in many organisms like fireflies and many marine animals. They are an impressively strong species as Jocelyn was able to cause Monroe much pain while squeezing his hand.

As the pregnancy advances, the female Glühenvolk needs to consume a greater quantity of cow ovaries to prevent the premature delivery of the child. During the third trimester, the female is no longer mobile enough to endure the physical nature of the hunt. During this time, the male Glühenvolk will harvest the ovaries for his mate during the night under the cover of darkness.

Behavior
Glühenvolk are a benevolent species, they do not like to kill accidentally or intentionally. Male Glühenvolk are extremely caring and protective of their mates especially if their mate is pregnant. When a female Glühenvolk is pregnant, she must consume cow ovaries to stay healthy and due to their disdain for violence, Glühenvolk prefer to attack the cows while they are asleep to lessen the rush of adrenaline, and thus, souring the flavor and texture of the meat.

Excerpt from Grimm Diaries
Thought to be extinct, Glühenvolk were considered valuable for their skin's luminescent quality and were hoarded by collectors.

It was thought to be extremely good luck to see a Glühenvolk in the wild.

Their existence and the likelihood of seeing one, was akin to the legend of the leprechaun.

Trivia

 * Vincent and Jocelyn's baby was the first woged baby seen on the show.