Dave Grohl’s heavy-metal project was Probot, an all-star recording project that became a 2004 album.
Grohl began developing Probot after years in Nirvana and while leading Foo Fighters. He recorded most of the instrumental tracks himself, drawing on the metal and underground rock bands he admired as a teenager. The project let him return to heavy, aggressive music that differed sharply from Foo Fighters’ alternative-rock sound.
Rather than operate as a conventional band, Probot featured different guest vocalists on its songs. The contributors included Lemmy from Motörhead, King Diamond, Max Cavalera, Cronos from Venom, Lee Dorrian and Wino. Grohl designed tracks with particular singers in mind, making the album a series of collaborations.
The album Probot was released by Southern Lord in February 2004. A common mix-up is calling Probot a permanent band; it was primarily Grohl’s studio side project, created as a tribute to the heavy-metal artists who influenced him.