Galeanthropy

"That is the most interesting delusion I've come across since reading up on galeanthropy," said Sophie. […] / "What's galeanthropy?" I asked. / Sophie said, "It's the delusion that you've been turned into a cat."

Meanwhile his frau made loud mewling and scratching noises in the hallway beyond, deep in the throes of advanced galeanthropy.

One of the finest novels for children ever written, in my opinion, is Paul Gallico's The Abandoned, in which a young boy named Peter, struck by a van while running across the street to pet a cat, falls into a coma and experiences galeanthropy.

You got through to him?! He [Jack Kevorkian] won't return my calls anymore and his secretary just keeps repeating "No, we don't think suffering from galeanthropy makes one a valid candidate for the doctor's consideration."