When you play in a world-conquering, gazillion-selling band of Metallica's stature, you're bound to attract a few oddball fans over the course of your career. Still, the metal titans' most unexpected devotee is quite a doozy: Richard Ramirez, the '80s serial killer known as the Night Stalker.

Metallica guitarist Kirk Hammett said Ramirez — the serial killer, rapist and burglar who embarked on a Los Angeles crime spree from 1984-85 and was sentenced to death in 1989 — was incensed when he heard the band performing at San Quentin State Prison in 2003, where they filmed their "St. Anger" music video, and wasn't allowed to see them.

"When we played San Quentin Prison [in 2003], he was on death row and could hear us," Hammett recently told NME. "The guards who were responsible for watching him said Richard Ramirez was pissed off and pacing his cell because he wasn't allowed to see us. He gave the guards his subscription copy of a magazine with us on the cover and on the mail-tag it said: 'Richard Ramirez, San Quentin Prison.' So that’s my little token from Richard Ramirez. Not to glorify the guy — he did some horrible crimes."

Watch Metallica's 'St. Anger,' Filmed at San Quentin State Prison

Hammett, a Bay Area mainstay who played in the thrash band Exodus before joining Metallica, also considered whether he and Ramirez ran in the same scene in the '80s. "He hung out in Richmond, California, and I wonder sometimes if me and the guys from Exodus were at the same parties as him back in the day," the guitarist mused.

Ramirez died in 2013 at age 53 due to complications from B-cell lymphoma while on death row. Metallica have since released two more studio albums, 2008's Death Magnetic and 2016's Hardwired... to Self-Destruct, and Hammett released his debut solo EP, Portals, in April.

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