Kephn

The Kephn is a form of vampiric witch from the Karen people of Burma. They resemble severed human heads with their stomach hanging underneath but normally look like regular people. They’re believed to be people who made a deal with evil spirits for power. They hunt at night and are thought to feed on human souls. They sit in a chair and enter a trance to transform themselves into their monstrous form by tearing their head and stomach free. They can be killed if their body is burned when their heads are out flying and they can easily be killed in human form. A trained fighter known as a Ghurkha, with a kukri, can fight them one-on-one. Some believe they can send out their spirits to take over newly deceased corpses, which are then also called Kephn. These corpse-Kephn are near invincible and can only be stopped through fire or decapitation.

Citations:

Maberry, Jonathan. Vampire Universe: The Dark World of Supernatural Beings That Haunt Us, Hunt Us, and Hunger for Us. United States, Kensington Publishing Corporation, 2006.