Draugr possess human-level intelligence, super human strength and can increase their size at will!
In Norse mythology, the Draugr is not someone you want to run into. Much like zombies, these undead creatures still have their physical bodies. Unlike most zombies, they possess human-level intelligence, super human strength and can increase their size at will.
After a Viking died, the main signs that they would become a Draugr is that the corpse was not in a horizontal position but found in an upright or sitting position. Any greedy or miserly person was usually a candidate to become a Draugr after death, living in their graves and guarding their treasure within their burial mound.
Regardless of how they were in life, the Draugr were monsters whose whole M.O was killing the living, and anyone killed by a Draugr was destined to become one themselves.