Notorious 1960s serial killer Charles Manson has sent Marilyn Manson an open letter from his prison cell. The rocker, whose real name is Brian Warner, took the latter half of his moniker from Manson's surname and his first half from actress Marilyn Monroe. A number of Manson's bandmates took similar stage names, with the likes of Twiggy Ramirez, Ginger Fish and Madonna Wayne Gacy also inspired in the same way. The postcard, which leaked online via Loudwire earlier this week, is largely abstract, but has a slightly threatening undertone to a number of its passages.