A Papuan tree spirit. The male is described as an ordinary man, but the female has one large and one small breast. Matagaigai only appear to people when they are ill: should their fingers sink into the patientapos;s flesh, then death is certain. Malevolent are the swamp spirits, or matabiri, ugly creatures with huge bellies and swollen cheeks. They like to put ‘medicine’ on people.