Tool

Tool's greatest breakthrough was to introduce dark, vaguely underground metal to the preening pretentiousness of art rock. Or maybe it was introducing the self-absorbed pretension of art rock to the wearing grind of post-thrash metal -- the order really doesn't matter. Though Metallica wrote their multi-sectioned, layered songs as if they were composers, they kept their musical attack ferociously at street level. Tool didn't. They embraced the artsy, faux-bohemian preoccupations of Jane's Addiction while they simultaneously paid musical homage to the dark, relentlessly bleak visions of grindcore, death metal, and thrash. Even with their post-punk influences, they executed their music with the ponderous, anti-song aesthetic of prog rock, alternating between long, detailed instrumental interludes and tuneless, pseudo-meaningful lyrical rants in their songs.