Body parts disappear
Vanishing Sickness was a wizarding illness which possibly caused the infected person's body parts to disappear. It was a contagious disease, provoked by a magical bug.
The section of "Magical Bugs" at St Mungo's Hospital for Magical Maladies and Injuries treated this disease.
Behind the scenes
- Xavier Rastrick was a famous wizard entertainer who vanished unexpectedly before the eyes of three-hundred people during a tapdance routine in 1836 and was never seen again. This might have been an instance of vanishing sickness or other unexplained magical phenomenon.
- Harry Potter and the Order of the Phoenix (Mentioned only)