An informally diagnosed psychological disorder, falling on the obsessive compulsive spectrum, characterized by an unremitting fixation on anything related to felines, either wild or domestic.
My elderly catcrazy aunt constructed a complex tunnel system inside her house by carefully arranging everything she had hoarded over her lifetime, solely for the enjoyment of her cats!
When a person loves cats so much, they start believing they ARE a cat.
The boy was catcrazy. He often meowed and purred, and he hissed at dogs. He climbed fences and trees, then needed the help of the fire department to get down.