Draugr

Origin: Norse mythology
Habitat: Graveyards/Gravesite
Behavior: Aggressive

Description: 

• They are dead bodies usually swollen, blackened or dead blue skin, and generally hideous to look at. Their bodies are described as being extremely heavy.

Facts:

• Draugar live in their graves, often guarding treasure buried with them in their burial mound, wreak havoc on living beings, or torment those who had wronged them in life. They are animated corpses — unlike ghosts they have a corporeal body with similar physical abilities as in life. Older literature makes clear distinctions between sea-draugar and land-draugar. Draugar possess superhuman strength, can increase their size at will, and carry the unmistakable stench of decay. They are also noted for the ability to rise from the grave as wisps of smoke and "swim" through solid rock, which would be useful as a means of exiting their graves. 
• In folklore, draugar slay their victims through various methods including crushing them with their enlarged forms, devouring their flesh, devouring them whole in their enlarged forms, indirectly killing them by driving them mad, and by drinking their blood. Animals feeding near the grave of a draugr may be driven mad by the creature's influence. Draugar also exhibit an immense and nearly insatiable appetite.
• After a person’s death, the main indication that the person will become a draugr is that the corpse is not in a horizontal position. In most cases, the corpse is found in an upright or sitting position, and this is an indication that the dead might return. Any mean, nasty, or greedy person can become a draugr. Draugar refuse to follow the prescribed path of death, selfishly staying on Earth when they are supposed to move on. Draugar can also come about through infection by another draugr such as in the story of Glámr. 
• Draugar are noted for having numerous magical abilities (referred to as trollskap) resembling those of living witches and wizards such as shape-shifting, controlling the weather and seeing into the future. Among the creatures that a draugr may turn into are a seal, a great flayed bull, a grey horse with a broken back but no ears or tail and a cat that would sit upon a sleeper's chest and grow steadily heavier until the victim suffocated.
• Draugar have the ability to enter into the dreams of the living, Draugar also have the ability to curse a victim. Draugar also brought disease to a village and could create temporary darkness in daylight hours. While the draugr certainly preferred to be active during the night, it did not appear to be vulnerable to sunlight like some other revenants. A draugr's presence may be shown by a great light that glowed from the mound like foxfire.
• Some draugar are immune to weapons, and only a hero has the strength and courage needed to stand up to so formidable an opponent. In legends the hero would often have to wrestle the draugr back to his grave, thereby defeating him, since weapons would do no good. Although iron could injure a draugr, as is the case with many supernatural creatures, it would not be sufficient to stop it. Sometimes the hero is required to dispose of the body in unconventional ways. The preferred method is to cut off the draugr's head, burn the body, and dump the ashes in the sea; the emphasis being on making absolutely sure the draugr was dead and gone.