Rain pours down outside, and the distant sound of thunder crashes through the sky. Then, like no moment in music before, the striking of a single guitar chord kick started a genre and provided generations of angry teenagers with a sound they could relate to. People can argue endlessly about the first Led Zeppelin album or the brutal sounds coming from Detroit that preceded this, but "Black Sabbath" is really where heavy metal began. From the imagery to the look and the sound, Ozzy Osbourne and company are the undeniable godfathers of the genre. With this song they sapped the blues out of garage rock and replaced it with a naïve self-importance that inspired legions of like-minded kids to pick up a guitar and sing about the devil. The three-note riff that pours from Tony Iommi's remaining fingers sounds like nothing before it -- distorted, discordant, and ungodly slow. Drummer Bill Ward pounds his drums like a caveman alerting the tribe of something bad, and indeed, something bad arrives. Armed with the most unique banshee wail in rock, Ozzy's first impression on the music world was a strong one. "What is this that stands before me," he barks over the minimalist soundscape, "A figure in black points at me." With two lines and a good riff, the band had suggested the sort of Dungeons and Dragons imagery that would feed its imitators for years to come, while alternately leaving so much to the imagination that artists as diverse as Nirvana, the Cardigans, the Butthole Surfers, and Big Country would admit their love for the heavy metal foursome. By the time bassist Geezer Butler shows up to carry the song off to its galloping conclusion, Osbourne has already begged God for help but to no avail. "Satan's coming 'round the bend," he sings, "people running 'cause they're scared." And mainstream critics, who had never heard such dark lyrics and brooding music sound so heavy, did exactly that. Black Sabbath was roasted by the press and shunned by the media for years, until finally it became obvious that heavy metal, not punk, was the mainstream voice of disenchanted suburban youth. And by that time, Osbourne was a drug addict who made better headlines than music, and Sabbath was a washed-up joke that Iommi couldn't bring himself to end. It only goes to show that the kids really are right, and Sabbath would pass on that knowledge to every metal band that rose up in its footsteps. The band had better songs and made much better albums, but this song was the defining creative moment of Black Sabbath's career.