The mistress of the dark is kissing the stage goodbye. Elvira is retiring as a live performer after nearly fifty years in the entertainment industry, according to The Gazette. She's set to appear in her final show at Knott's Berry Farm, where she's been headlining Halloween performances for 21 years, on Tuesday. "I just decided that, you know, doing live shows is really difficult and it takes up a big chunk of time every year," Elvira, born Cassandra Peterson, told The Gazette. Although she's through with on-stage performances, the queen of Halloween isn't hanging up her sexy black gown for...