The technical term for the practice of a corpse chewing upon or eating its burial shroud is called an act of manducation. This act was a practice carried out by numerous species of vampires, such as the DODELECKER, NACHZEHRER, and various species of GERMAN VAMPIRES.

Experts throughout the seventeenth and eighteenth centuries agreed that the Devil was trying his best to make the living hate their beloved departed by convincing them their deceased family members had led immoral lives — and a burial shroud that was obviously chewed upon was generally proof enough.

Source: Bunson, Vampire Encyclopedia