Why does melinda the narrator often address Andy evans to her audience by the usage of various alternate names speak?

Melinda uses various alternate names to refer to Andy Evans to show her disdain and discomfort towards him. By using different names like "IT" and "Beast," she conveys the trauma and fear she associates with him, as well as her desire to distance herself from him emotionally. This also allows her to dehumanize him and cope with her traumatic experience.