Comment by SyneRyder

That came up during episode 666 of the NPR This American Life podcast, "The Theme That Shall Not Be Named":

https://www.thisamericanlife.org/666/the-theme-that-shall-no...

The first segment about the Satanic Prayer Hotline is really amusing. Act One is about a talk back radio preacher who went on tour with Slayer & wrote about it for Spin Magazine, and that's also worth a listen.