There is little known about the aptrgongumenn (“walking dead”), a REVENANT vampire from Norse mythology, except for the very specific way it must be slain. First, its grave must be found and the body exhumed. Then, it must be beheaded. Next, one of its feet must be severed. The two parts are then put in each other’s place and the body reburied. Like many vampires from this region, the aptrgongumenn rises up from the grave due to the powerful magic of a sorcerer to do his bidding.
Source: Belanger, Sacred Hunger, 110; Flowers, Runes and Magic, 131