The draugr appears throughout Old Norse and Icelandic saga literature as a physically animated corpse that remains in or near its burial mound, retaining much of its living strength, its grudges and often a supernatural increase in both. Sagas such as Grettis saga and Eyrbyggja saga describe draugar as capable of crushing livestock, driving farms to ruin through fear and misfortune, wrestling the living with monstrous force, and in some cases growing larger or heavier in death than they were in life, a detail scholars read as marking the corpse's continued unnatural vitality. Causes vary across the sources: a person of malicious, greedy or generally difficult temperament in life was considered likelier to walk again, and burial itself could go wrong, so some saga heroes take pains to bury a dangerous person with specific precautions meant to keep the body from rising.
Unlike ghosts in the modern sense, the draugr is emphatically physical, smelling of decay, leaving tracks, and requiring physical combat rather than exorcism to put down, most famously beheading the corpse and burning the remains, or otherwise removing and disposing of the head separately from the body so it cannot be reattached.