Madame X is a mysterious woman who wants to trap Billy Joe Cobra's ghost in a jar for her collection of BJC memorabilia. Sam Hoover, the man who constantly tries to kidnap Billy, is her henchman acting under orders.
Madame X has purple hair, pale skin, and a gap between her front teeth. Her full face has never been shown.
Interestingly, none of the other characters know what she looks like, either. Billy's photos of her only involve her lower face and hands.
Madame X seems to be a very cruel and selfish individual, seeing as she constantly mistreats Sam Hoover and has a desire to kidnap and store away Billy's ghost for her own purposes. She doesn't seem to regard others' feelings in any way, shape, or form.
Most evidenced by her feelings toward Billy, she has an incredibly obsessive and possessive nature. This aspect of her personality is not limited to Billy alone, as seen in Billy's Achilles, wherein she attempts to trap Hugh Wright in her estate after he acted as her life coach.
She appears to know the rules regarding ghosts, outfitting Hoover in Billy's underwear. Perhaps she has even more knowledge than that, as she also equipped Hoover with a fully-functioning ghost containment gun.
Madame X may be a Southern belle. While Hugh was acting as her life coach, she had corn growing in her lair, she played the banjo, and she was shown milking a cow.
Billy Joe Cobra
Though Madame X herself can barely be seen from behind her large chair, it is apparent that she is a huge BJC fan. Her walls are covered in posters of Billy, her earrings are in the shape of Billy's face, and she knows every single obscure trivia fact about him, including his favorite animal, favorite food, and all the statistics regarding Billy's hit singles.
She is so crazy about Billy, she wants to capture him and put him in a jar as the crown jewel of her collection. Luckily for Billy, she never succeeds.
Nothing appears to irritate Madame X more than seeing her henchman fail at his job of collecting Billy. She has always been cruel to Sam, threatening to put him back on a diet of cat food if he does not succeed and yelling at him when Spencer Wright manages to foil their plans.
Regardless, Hoover seems to be incredibly devoted to her, suggesting that he thinks there is something good about her. (No other character on the show would agree with him.)