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."

Source: wiktionary

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

Source: wiktionary

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.

Source: wiktionary

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."

Source: wiktionary