"...from the very depths of hell.  VENOM!!!!"

If you're not familiar with Venom, they're part of the New Wave of British Heavy Metal, and are often cited as one of the founders of black metal (the others being Celtic Frost and Mercyful Fate).

Venom's schtick back in the day was that they were satanists.  All their songs were about the devil and how they were in league with Satan and they hated priests and anything that wasn't the devil.  When word got out that Venom's "satanic rites" were just a way to sell records, the black metal bands after them were pretty upset.

Back in 1980, Venom submitted a demo tape to EMI and here's their response.

Venom's Rejection Letter
 

I really hope this is real, but part of me thinks it's not.  Anyways, go listen to the first three Venom albums, "Welcome to Hell," "Black Metal," and "At War with Satan."  You'll thank me later.