The world's most famous goth has been accused of many things during his career, most of which he turned out not to have done. One report said he'd killed animals on stage; others that he'd inflicted injuries on either himself or people in the front row, as well as performing Satanic rites and burning Bibles. None of those things actually happened, but they generated fantastic press for the heavy metal band that bears his name.
He probably wouldn't have been able to persuade fans of that genre to take him seriously if he'd just gone by the name his parents gave him: Brian Warner. There are very few world famous Brians out there! His stage name comes from a grizzly place; wanting to combine beauty and horror, he took the first name of Marilyn Monroe and the last name of Charles Manson. The intent was to shock. It worked.