Earlier this week, Mastodon confirmed their new Marrow Deep album is on the way, and that it features guest spots from friends like Queens of the Stone Age’s Josh Homme. Another metal icon now confirmed to be on the LP is none other than Black Sabbath co-founder Geezer Butler, who threw down the bass intro to the upcoming album’s “The Vanishing.”
Speaking with Bass Player, Mastodon bassist Troy Sanders said that the group’s ninth album features a notable “bass highlight…but it isn’t me.”
He adds that the band asked Geezer about getting on-board for Marrow Deep shortly after Mastodon performed at Black Sabbath’s Back to the Beginning farewell show in the summer of 2025. There’d been history between the two bands well ahead of this — they toured together in 2005 as part of Ozzfest, while Butler namedropped his love of Mastodon in his autobiography, From Birth to Black Sabbath—And Beyond. For those reasons and more, they reached out and asked him for a bass line.
“We wanted him to hear where the record was going and see if anything inspired him, and he sent back this incredible bass solo that became the introduction to a song called ‘The Vanishing,’” Sanders confirmed. “It’s a very Sabbath-inspired track. It’s definitely the bass highlight of the album. And I’m completely happy saying that.”
Sanders added that Butler’s bass section was recorded remotely.
“Everything went through management. We’ve never actually met face to face. At the Sabbath show at Villa Park, it was a madhouse in the Sabbath area, so the idea of trying to go back there just didn’t feel right.
“We’re hoping to finally meet when we’re touring the States later this year because he’ll be near one of our days off. If we can actually sit down together, that’ll complete the whole circle.”
Marrow Deep was recorded in Atlanta, Georgia, with co-producers Patrik Berger and Kurt Ballou. Notably, another recent interview with Kerrang! had Mastodon confirming that the album also features contributions from Ballou’s Converge bandmates Nate Newton and Ben Koller, while the record also has guest appearances from Lamb of God’s Randy Blythe, Gojira’s Joe Duplantier and Clutch frontman Neil Fallon.
It’s the first Mastodon record since the 2025 passing of founding guitarist Brent Hinds. It marks the debut release with Canadian guitarist Nick Johnston, and also features significant contributions from keyboardist João Nogueira.
Marrow Deep is out August 28 via Loma Vista Recordings and can be pre-ordered in an array of collectible formats — including Revolver-exclusive vinyl variants on “eco-friendly green blend” and “eco-friendly magenta blend” wax — in our shop.
Mastodon’s “The Poisonous Weapons Tour” begins September 16th in Orlando, Florida. You can peep the full itinerary here.