Stephen Bier was born in a Jewish-Catholic family, and was given Ritalin as a kid to treat his hyperactivity. He was studying data processing and architectural design when he met Mr. Manson and Olivia Newton Bundy at a Florida nightclub.

Original keyboardist Zsa Zsa Speck had quit after only playing a few shows, and the band settled on Bier to replace him, despite the fact that he had no experience on keyboards at that point. Bier was christened Madonna Wayne Gacy, after pop singer Madonna and John Wayne Gacy, the infamous serial killer who raped, tortured, and murdered over 30 young men and buried them in his basement. J.W. Gacy also performed at children's parties as Pogo the Clown, from which M.W.Gacy takes his nickname.

During MWG's first several shows with the Spooks, he simply sat on stage and played with green army men because he didn't have enough money to buy a keyboard yet. He often could be found during performaces in a section labeled "Pogo's Playhouse" wearing a clown costume.

He has also managed to be the only member from the Spooky Kids days that has stayed with Manson to the current period, the only constant in a revolving door of musicians over the years.