Slayer - Haunting the Chapel - August 4, 1984
This EP, this little tiny 3-song EP is where thrash becomes THRASH. It's almost immediately recognizable. As "Chemical Warfare" kicks in, there's a noticeable increase in darkness, in aggression, in violence... and then Araya comes in sounding like a demented madman and it's settled: this is what thrash will be. "Chemical Warfare" is easily the best song here, and among the best in Slayer's vast catalog. The other two are still good, just a little less so. The title track really has an "Angel of Death" vibe going on during the verse. The guitar solos are a little more towards that dissonant style that Slayer would develop later but still pretty good, and Lombardo still isn't amazing either. This is some quality, early thrash though. I just wish there was more of it.
Standouts: All three songs, but especially Chemical Warfare