In September of 1985, Glenn Danzig mailed a letter to Cliff Burton regarding Metallica's plans to record Misfits covers.

Of course, there is a sad and twisted end to this story because, as fans know, Metallica's Misfits covers were not released until 1987, after Burton's tragic death.

Burton's punk fandom was well-suited for his role in the band that pioneered thrash metal, even if his songwriting prowess and knowledge of musical theory contrasted punk's rudimentary barrier to entry. The tattoo of Misfits' "Crimson Ghost" mascot on his right shoulder really said it all.

Danzig's Letter to Cliff Burton

It appears Metallica had reached out to Danzig about wanting to cover the Misfits song "Green Hell."

As shown on the Instagram page of Danzig fan site "7th House," a three-image slideshow displays the postmarked envelope, followed by Glenn Danzig's message for the bassist.

READ MORE: Metallica Launch Digital Cliff Burton Exhibit in Online Museum

The account states that the envelope is dated Sept. 24, 1985 and concerns the aforementioned Misfits song. It was mailed via Plan9, the record label Danzig founded in 1977 and ran through 1995, and arrived at Scandinavia Hotel in Lars Ulrich's hometown of Copenhagen, Denmark.

Danzig drew a border of bones around the mailing address and even drew a skeletal figure with his signature "devilock" hairstyle.

The letter reads:

I don't usually let people cover out stuff, but you guys are about the only band who can do it and not butcher it. If you do butcher it, GRRRRR..... Beware my vengeance!!! (I doubt you will). That's about it, if there's any problem w/publishing co.'s have 'em give me a buzz. Later, killer.

—Glenn Danzig

Metallica's Cover of "Green Hell"

On 1987's The $5.98 EP - Garage Days Re-Revisited, Metallica covered "Last Caress / Green Hell."

The EP was also Metallica's first release with Jason Newsted on bass, who had left Flotsam and Jetsam to join the group in 1986 after Burton's death.

"Last Caress" has endured as one of Metallica's most popular live songs, having been played more than 800 times. That's more times than they've played Diamond Head's "Am I Evil"!

As for "Green Hell," however, that's quite the rarity, having only been played 12 times. The first was in June of 1989 with December of 2011 being the latest, where Danzig joined Metallica onstage at a 30th anniversary show. Watch footage from that night directly below.

Glenn Danzig Joins Metallica for Misfits Covers (Dec. 9, 2011)

Most Played Cover Songs By 50 Big Hard Rock + Metal Bands

We combed though setlists of the biggest names in rock and metal to find out their most played cover songs. (OK, so we actually used Setlist.fm. What, did you think we had a pile of setlists sitting around?)

Gallery Credit: Rob Carroll