TOOL have always relished flouting rock ’n’ roll conventions—whether that takes the form of concerts where frontman Maynard James Keenan sings while shrouded in darkness or 11-minute-plus songs released as singles. But like the ambitious groups the quartet count as influences (e.g., King Crimson, Pink Floyd), TOOL have amassed a deeply loyal fanbase and a catalogue full of complex, rewarding music and visuals. The band formed in early-’90s Los Angeles, after Keenan—who had been performing with the theatrical visual project Green Jellÿ—and guitarist Adam Jones teamed up with drummer Danny Carey, another Green Jellÿ associate. Carey's CV as a session player notably (and surprisingly) included work with Carole King. A simmering cauldron of grungy, angst-ridden alt-metal, TOOL’s 1993 full-length debut, <I>Undertow</I>, spawned the propulsive hit “Sober”, which came paired with a groundbreaking stop-motion video co-directed by Jones. Over time, the band’s studio albums emerged less frequently—2020’s <I>Fear Inoculum</I> came 13 years after the band’s previous album, <I>10,000 Days</I>—but became more intricate; the music took cues from prog metal, space rock, stoner metal and post-rock. In TOOL’s absence, a cavalcade of alt-metal bands formed and carried on their ambitious legacy by forging their own boundary-pushing paths.