A 48-year-old man in the UK contracted a previously unknown species of bacterium after being bitten by a stray cat. Within hours, his hands swelled significantly, leading to emergency medical attention. Despite treatment, his condition worsened, requiring surgery and intravenous antibiotics. Doctors identified the bacterium as a distinct and previously undescribed species belonging to the Gram-positive bacteria genus Globicatella. This discovery highlights the potential for cats to carry undiscovered bacterial species with human pathogenic potential. Cat bites and scratches, which lead to thousands of emergency department visits annually, underscore the importance of prompt medical care following such incidents.