In Charlie Stross’s Laundry Files books, there are horrifying demon parasites from alternate dimensions that can eat your tongue (and, um…other body parts – why spoil it?) and live in your mouth, while turning you into a sort of zombie. A horrifying idea, but these books are fun, tongue-in-cheek (oops…) highly entertaining and recommended (by me). Anyway, it looks like he got the idea from an IRL horrifying parasite that is about a third of an inch long and can indeed eat your tongue and live in your mouth – if you are a fish. Gross.