I read a book in a library around 2000AD that I have been trying to remember since.
A town of people is suddenly (or not so suddenly) transformed into creatures, monsters, or people of a fantasy nature. At least one townsfolk turned into a bear.
Of the main characters there was one male who turned into a "hero", a female who turned into a nymph/dryad and another female who turned into a griffin.
The main characters originally thought they had escaped the random transformations until over time they changed as well, with the griffin girl quite upset about it until someone told her that a griffin was a symbol of honor and pride or something to that effect.
The cause of the transformations was a mystery and the main characters were I believe trying to discover it.