Charles Manson, despite (or rather because of) his infamy as a charismatic cult leader and vicarious spree-killer, is often posed as a serious and influential musician. His fleeting connections to late-60s artists of repute are threaded into music history as metaphors for the dangerous genius and subversion of rock itself, a flame occasionally nursed by covers released by popular artists. But Manson wasn't a genius and his music is crazy trash. People only say otherwise because of the murders.
The BBC reviews his oevre:
Manson's closest brush with musical fame came after Gary Hinman, a music teacher who would later be one of the family's victims, introduced him to Dennis Wilson of the Beach Boys.
Wilson took one of Manson's songs, Cease To Exist, and turned it into the Beach Boys' song Never Learn Not To Love – taking a full writing credit for himself, after changing some of the lyrics and adding the band's famous harmonies. Manson reportedly received a one-off payment and a motorcycle in exchange for the rights to the song, but he came to resent Wilson's "theft".
Charles Manson's music exemplifies the narcissist's competence. They get just good enough at something to hook you uneasily on a first impression you're doomed to regret.
Trent Reznor briefly rented the house made famous by the Tate murders, naming it "Le Pig" after the word scrawled in blood by one of Manson's Family there, and he regretted it. From a Rolling Stone interview.
While I was working on Downward Spiral, I was living in the house where Sharon Tate was killed. Then one day I met her sister. It was a random thing, just a brief encounter. And she said: "Are you exploiting my sister's death by living in her house?" For the first time the whole thing kind of slapped me in the face. … When she was talking to me, I realized for the first time, "What if it was my sister?" I thought, "Fuck Charlie Manson."