- "Anyway, this time Willy's been caught selling biting doorknobs to Muggles and I don't think he'll be able to worm his way out of it because, according to this article, two Muggles have lost fingers and are now in St Mungo's for emergency bone re-growth and memory modification. Just think of it, Muggles in St Mungo's! I wonder which ward they're in?"
- —Arthur Weasley talking about work.[src]
A biting doorknob is a door handle which has been jinxed to snap at the fingers of anyone who tries to turn it. Willy Widdershins was caught selling these items to Muggles in 1995. Two of his victims lost fingers and had to be sent to St. Mungo's to have their bones regrown and their memories modified.
- Harry Potter and the Order of the Phoenix (Mentioned only)