Norwegian folklore i

Nøkken is a shapechanger from Norwegian folklore who lives in lakes and rivers. He transforms into a beautiful white horse, a knight or a maiden, or even a necklace, and lures people into his depths. 

Fossegrimen (The Grimm of the Waterfall) is a nordic shapechanger that lives in rivers and waterfalls. He lures people to him with his harp or his fiddle, as he is the most talented musician of the Vette. People say that legendary fiddle players sought him out to teach them how to play, bringing an offering or selling their soul to him. 

Tusser (Also know as the Invisible People or the Underground People) are small human-like creatures from Norwegian folklore. They live underground yet lay claim to the land above them, and are extremely territorial and willing to harm, scare, or prank humans who trespass on their turf. They have the power to inflict bad luck up others, and like to stay invisible. 

Draugen is the spirit of a sailor who passed away at sea, and thus could not be buried in holy ground. Seeing it or hearing its gurgling calls means that storms, bad luck, and disaster will follow. It can be defeated by finding its fetters - such as clothing from their original wreck - and burying it above the water line. The modern stories of draugen come from the fishing communities of Northern Norway, and their close relationship with the Norwegian and Barents seas. This concept of the spirit is an evolution of the mound-dwelling Draugr of medieval norse belief.

Nisser are the quintessential nordic fantasy creature (or at least, a solid second place to trolls), and function as hearth spirits in homes and farms. If you feed them and respect them, they will help you with the animals and the chores, though if you anger them they cause bad luck and perform mean-spirited pranks. 

Popularised by Elder Scrolls' Skyrim, the Draugr is the older norse perception of draugen. The Draugr is a coporeal or incorporal creature tied to its burial mound. It resembles the figure they were in life, and has access to the treasures they were buried with. 

One appears early in the Saga of Grettir the Strong, called Kar the Old. He haunts the island of Haramsøy, driving away all farmers except those working for his descendants and battles Grettir when he breaks into his mound. 

Another common story and motif of the draugr is the fairy tale "The Golden Horn", where a drunken man approaches a mound he knows one lives in. He calls out "Give me a drink!", at which point the creature appears and offers him a golden drinking horn. The man takes fright and rides off with his horse, though the draugr chases after him and chucks the horn after him, causing a few drops to spill on the horse who is immediately burned by the supernatural alcohol. The draugr keeps hunting the man until he reaches a church and scares it away by ringing the church bells. After that the man, thankful, donates the golden horn to the church, where it still rests today.