The story of the collaboration, as told by Rolling Stone:

Minutes before Mastodon performed “Black Tongue” on the U.K. talk show Later… with Jools Holland last October, the sludge rockers were marveling at Leslie Feist from behind the scenes, as the singer-songwriter charged through two tunes from her Metals album with her own band. “They were great,” guitarist Bill Kelliher recalls to Rolling Stone. In fact, Mastodon were so impressed, they instantly decided to work with the singer. We thought, “Why don’t we see if they want to collaborate somehow, someway?” Kelliher says.

Feist was initially unaware of the band’s plans. “Next thing I know, they had announced on MTV that they were gonna cover a song [of mine],” she remembers, laughing. But soon, she returned the favor, resulting in an oddball one-off collaboration called Feistodon – a split-single that will be available in stores for one day only on April 21st, in celebration of Record Store Day. “It’s a wet dream to have Mastodon take one of my songs and put it into their massive machine,” says Feist.

Both artists let each other choose which song to cover, which led to Feist recording a version of “Black Tongue” and Mastodon to picking Feist’s “A Commotion.” Says Kelliher, “We didn’t tell her what to do, and she didn’t tell us what to do. ‘A Commotion’ just kind of stuck out to me. I could hear the opening riff, a single A-note.”

Feist, meanwhile, says her decision was guided by which song’s lyrics resonated with her the most. “Mastodon fans would probably be disappointed to know that I actually didn’t know Mastodon very well. I actually went onto one of those lyric websites, and I scrolled through 50 songs and just narrowed it down to the ones I thought I could wrap myself around the words of,” she explains. “‘Black Tongue’ is speaking in my kind of language – about diamond and earth and sky. It was pretty easy to climb into that one.”

Feist recorded her “Black Tongue” cover during an eight-hour layover in Los Angeles; Mastodon knocked out “A Commotion” amid a jam-packed European tour. Feist didn’t veer too far from her musical path. “Of course I’m not going to try to be Mastodon,” she says. “My drummer isn’t gonna be doing Morse-code, double kick drum patterns. You’re going to take it into your own universe.” Feist describes her aproach to the tune as “textural rather than laser-beam, flamethrower time-precision. For me it’s much more atmosphere – creating my version of what metal is.”

“It’s really cool,” Kelliher says of Feist’s cover. “It’s very haunting the way that she sings, ‘I cut off my tongue.’ This dainty girl singing these brutal lyrics. It kind of sent chills up my spine when I heard it.”

Of his band’s version of “A Commotion” – on which Mastodon bassist-singer Troy Sanders handles vocals – Kelliher says, “We got the broad swords and strapped on all the armor that the song didn’t have before. We did as much as stuff on it as we could to make it very Mastodon-esque – throwing open high notes in there, low guitars and heavy drums. Crazy sounds.

“Who knows?” adds Kelliher. “This could be the new Mastodon direction.”