Their first two albums, Opiate and Undertow, dabbled in alternative metal, post-metal, and even grunge influences. Their later albums, Ænima, Lateralus, and 10,000 Days, are progressive/art rock influenced. The band spans several genres and is one of the most influential metal bands in recent memory.
Often called the inspiration of the nu-metal genre, an enormous disrespect to Tool. When Tool was formed, they were one of the first alternative metal bands. Today, countless nu-metal bands copy this style and attitude, and all list Tool as their primary influence, despite only taking in the surface noise and angst from Tool and none of their depth, complexity, or talent. This mockery came to a climax when shitcore band Limp Bizkit did a cover of Opiate in concert, which was full of whines and lyrical mishaps. Worst of all, the 6-minute song was condensed to a 2-minute rap.
Tool's masterpieces include the songs; H., Forty-Six and 2, Eulogy, Sober, Jambi, Prison Sex, Opiate, Pushit, a cover of Led Zeppelin's classic No Quarter.
Guy 2: No man, you should check out Tool. They pioneered the post/alternative metal sound, and they are way more talented and they have way more depth and sincerity, and unlike KoRn, was not created as a manufactured product of pop culture.
Guy 1: No way man, KoRn is the ultimate modern metal band.
Guy 2: -hands guy 1 a copy of Tool's 2nd album, "Undertow", saving guy 1's dignity-