In China, there is a vampiric demon known as a kuei. Horrific in appearance, it possesses and animates the corpse of the recently deceased. It seeks out bodies that did not have proper burial rites said for them or performed properly. As it ages, the kuei gains the ability to fly with its corpse, but until that time, it is limited as to how it can attack. The kuei is incapable of climbing over even the simplest of walls or fencing.

Source: Latourette, The Chinese, 36, 164; Strickmann, Chinese Magical Medicine, 24-26, 72-75; Summers, Vampire: His Kith and Kin, 237; Werne, China of the Chinese, 231-233