I’m sure everyone reading this is familiar with H.P. Lovecraft’s short story, The Outsider. The Black Mass did it as an audio drama (not simply reading the story, but with sound effects, etc.) in the 1960s, and it is fantastic. Even if you’ve read the story, this version has an added dimension that you’ll enjoy. You can download it for free from my collection, at this link:
The Black Mass was a horror-fantasy radio drama produced by Erik Bauersfeld, a leading American radio dramatists of the post-television era. The series aired on KPFA (Berkeley) and KPFK (Los Angeles) from 1963 to 1967, on an irregular schedule (read more at Wikipedia).