For many Metallica fans, 2016's Hardwired … to Self-Destruct was a much more satisfying release than anything they’d heard for years. It appeared impossible that the band would ever fully embrace their thrash metal roots, but a number of tracks on Metallica's tenth LP were powerfully reminiscent of the past.

The final track, “Spit Out the Bone,” was one of the best examples. In a seven-minute high-energy burst, Metallica explored their history of staccato attacks, grinding riffs, angry lyrics and soaring solos. Every time their approach changed, it seemed to come back even louder and faster, delivering a relentless, satisfying reminder of how they’d turned heads on the breakthrough album Master of Puppets.

Metallica was inspired by a line in British punk band GBH’s track “Passenger on the Menu,” which told the story of a 1972 plane crash in Argentina were survivors were forced into cannibalism. Ultimately, however, frontman James Hetfield decided to explore another form of human risk.

“[It’s] just the wonder and fear of what’s happening to man,” he told Rolling Stone. “Without future tripping too much, just the possibilities of Terminator, stuff like that.” He added: “We could be a much more efficient race if we just allow computers to help us. And yeah, they are helping us, but how far does that go? All of that craziness. So ‘Spit Out the Bone’ is that your bones aren’t needed. They break.”

Lars Ulrich, who co-wrote “Spit Out the Bone,” said he knew it was best to leave Hetfield to develop the lyrics on his own. “He really went into his own world and dealt with all of that,” Ulrich said in a separate Rolling Stone interview. “The thing about him is he has the tendency to change lyrics a lot as he goes along from the first time I would hear it. You have to know not to attach yourself too much to them.”

Watch Metallica’s Video for ‘Spit Out the Bone’

Ulrich had offered plenty of feedback as Metallica worked on 2008's Death Magnetic – but this time, “I was not like that. I know him well enough to know when he wants me to get involved and when he wants to figure it out on his own,” he said. “Even at times where I could sense that he was struggling, I know when to hold myself back.”

The pair also adjusted their approach to the music: Death Magnetic had been the result of long conversations and careful planning, while “Spit Out the Bone” and its companion tracks were much more organic. “I think there is definitely more of a New Wave of British Heavy Metal thing on this record,” Ulrich told Rolling Stone. “It’s just a lot of banging riffs and rockin’ kinds of moments, as well as some straighter, simpler drumming. ... Unlike Death Magnetic, we just started jamming and playing. What was different, like with ‘Spit Out the Bone,’ is we started trimming it and making it leaner and thinner, more concise.”

The result, he added, was “an adventure, man.” Ulrich said he had “versions of that song that are two to three minutes longer. We just kept going and going and going. That was also the first song where we went, ‘Wait a minute, is there too much of a good thing here?’ And then we started peeling it back. It was one of those where you just keep going to different universes and different modes and areas because it was super fun. It was like this journey.”

“Spit Out the Bone” was paired with a dystopian sci-fi video by Phil Mucci, who had a history of working with heavy bands with heart, including Korn and Disturbed. The clip dug more deeply into the darker side of Hetfield’s thinking, in the style of a Terminator-like story where machines dominate humanity and begin forcefully turning people into cyborgs – with a hint of the suggestion that it’s for our own benefit because we’ve failed ourselves throughout history.

Watch Metallica Debut ‘Spit Out the Bone’ on Stage

Guitarist Kirk Hammett admitted some doubts about achieving a convincing delivery ahead of its first live performance. “‘Spit Out the Bone’ is the Mount Everest of the new album – the highest peak and the hardest ascent,” he told Variety. “On the rest of the record, I improvised my solos – not that one. The instrumentation on that song is so tight that I wanted to solo with equal precision.”

Released on Nov. 17, 2017 as the last single from Hardwired … to Self-Destruct, “Spit Out the Bone” quickly became one of their most-requested songs on tour. Still, Metallica didn't immediately debut it on stage.

“What seems to be a fan favorite now is ‘Spit Out the Bone,’” Ulrich said back then. “We’ll get to all of it, but I don’t think we’ll be introducing ‘Spit Out the Bone’ in a stadium. That’s a pretty deep song; I think it will work better in an arena.

“But listen, the fact that the fans have embraced the record at this level, the fact that they want to hear more, and the fact that we feel comfortable enough and open a stadium show with a new song,” he added, “it’s a testament to how awesome this record’s been received – way beyond our wildest hopes and imaginations.”

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