Bholgar

Like their near counterparts, draugr, bholgar are immune to weapons. They are also immune to most magic - only fire magic can harm them, and then at a reduced effectiveness. Their most powerful attack, however, is their ability to drain the life force (body power) from an opponent whom they are wrestling. For each round that they are in direct contact the Bholgar can drain one point from the person until they are completely weakened and dead. The Bholgr adds this to its own body power, making it even harder to kill.
Bholgr may also learn. This means that their skills can grow, unlike the draugr who is stuck with the skills it had as a mortal. They may also learn magic. When a bholgar drains the life from someone they gain one of that person's skills. This means that they can learn the spells of any whom they manage to drain completely, taking their victim's magic for their own.
Bholgar have all of the other abilities and invulnerabilities of a draugr.
A bholgar must go through the same ritual to be killed as a draugr, but the burial of its head must be done within a circle of silver that has the runes for journey (ᚱ), protection (ᛉ), Odin (ᚨ), Yngvi (ᛜ), and Thor (ᚦ) inscribed around the burial place, and they must remain in place for a year and a day, otherwise the bholgar may have the power to regenerate and arise once again. If this happens it will seek revenge on those who tried to destroy it.