Tool are a bona fide prog-metal juggernaut today, but in 1991, things were very different. Newly signed to a major label after playing just seven shows, the group — singer Maynard James Keenan, guitarist Adam Jones, bassist Paul D'Amour and drummer Danny Carey — were still making music as "a hobby," as Jones recalled to Revolver in 2013. "The vibe of the band was different at that point," Carey told us five years earlier. "We hadn't really defined the parameters between us or the way we interacted, and that made our sound more raw. There were a lot of boundaries being leapt over and lots more learning experiences happening at the same time, which was really exciting. Musically, we were just trying to find out what our personality was as a band."

Tool's 1991 debut EP, Opiate, only represented one side of that personality: the heavier, more aggressive side. The band already had about half of their breakthrough follow-up full-length, Undertow, written at that point, but, as Jones remembered, "Someone at the label was like, 'You guys gotta put out your heaviest stuff! That's how you're gonna get noticed!'" And noticed they were, thanks both to their recorded music and their far-beyond-intense live show. Below, see amazing and candid photos from '91 and '92, as Tool were finding their identity and making their name.

photograph by Lindsay Brice/Getty Images × photograph by Lindsay Brice/Getty Images