This group gathers Fungi subcategory members whose defining trait is a parasitic or disease-causing relationship with a human or other animal host, rather than with a plant, spanning fungi that infect people directly and fungi that specialize in infecting insects, amphibians or other animals. It spans human and mammalian pathogens such as Coccidioides, the cause of Valley fever, Pneumocystis, a cause of serious pneumonia in people with weakened immune systems, and Microsporum canis, a cause of ringworm in both animals and people, alongside insect-specialist pathogens such as Beauveria, Metarhizium, Cordyceps and the zombie-ant fungus, all of which kill their insect host and are studied both for their ecological role and, in several cases, for use as natural biological pesticides, and White-nose Syndrome Fungus, a cold-loving pathogen that has devastated North American bat populations since its accidental introduction. Malassezia, ordinarily a harmless part of the skin's microbial community on humans and other warm-blooded animals, is gathered here too for the opportunistic skin conditions it can cause when that ordinary balance is disrupted.