A sunny September Sunday in Volunteer Park: Parents and their offspring commingle with the hardcore electronic-music heads at Decibel Festival's climactic day in 2009. Onstage, a skinny, bespectacled, bushy-Jewfro'd DJ is getting hectic on the decks. Sporadically he bellows into the mic, mid-mix, big-upping and identifying the music he's spinning, peppering his informative asides with liberal usages of "motherfucker" and other terms of endearment for the throngs of revelers who are scarfing up this maniac's selections and exhortations. Delicate, youthful ears are being violated with vicious profanities and sounds that are both sacred and filthy, old and new, obscure and familiar, eclectic and psychedelic. After his set, which was the best of the fest for sheer showmanship and content, the crowd mobs him for GLK mix CDs and stickers—and to finish his whiskey and maybe to give him drugs. He leaves the stage CD-less and sticker-less. (Possession of illicit substances could not be confirmed.) A mother­fucking phenomenon is launched.

The Gaslamp Killer (aka 27-year-old L.A.-based William Bensussen; henceforth GLK) used to include the intensifier "Motherfucking" in his stage name; now he mostly relegates it to conversation, stage banter, and Twitter posts, for which he exclusively uses CAPS LOCK. Even if he's not billed as such anymore, the attitude behind the handle remains in full force.

GLK began DJing in San Diego's Gaslamp district at age 17, playing to military personnel, surfer dudes, assorted meatheads, and the ladies who love 'em—none of whom could fathom the value of what he was laying on their thick domes. In this hostile environment, GLK developed a combative spirit, if you'll allow an understatement. For some reason, the area's promoters kept booking GLK, even as he proudly, defiantly cleared dance floors with his "instrumental psych dirty beats."

A self-proclaimed "neurotic Scorpio Jew" of Turkish, Lebanese, and Mexican descent, GLK initially wanted to participate in San Diego's punk-rock scene, but he couldn't find anyone on his wavelength and his bass-playing stank.

"Then I started listening to rap shit, and then I went to a rave and saw one DJ controlling the whole crowd like a one-man band," GLK writes via e-mail while stuck in "worstfuxkintrafficjamever" on his way to a gig in Boston; such is his business now that he had to madly peck out his responses to The Stranger in these cramped, pressurized circumstances. "That's when I knew what I wanted to do. So I started buyin' records and practicing on my homie's turntables until I saved up enough to buy my own and practiced every fucking day. The rest is history."

A significant part of that history happens at L.A.'s Low End Theory, a weekly confab of audio research and development held at the Airliner, where GLK is an integral figure. There he swaps knowledge and inspiration before large crowds with DJ Nobody, Daddy Kev, D-Styles, Flying Lotus, Ras G, Daedelus, and other future-freaking beat scientists who have made SoCal one of the world's most fertile post-hiphop/post-dubstep hotbeds. For the last three years, GLK has been able to focus on his DJing and production skills, and the woodshedding and frequent gigging have paid huge dividends, to the point where he's now poised to upstage Prefuse 73 on their upcoming tour.

GLK's DJ sets stand out from others' due to their strange juxtapositions and rapid collision of styles and the wide range of genres he covers, which are bolstered by turntablist tricks and off-the-cuff commentary. Rampant diversity and seemingly illogical transitions reign, but rather than sounding clunky and dilettantish, GLK's shows dazzle through his incredible reflexes and knack for making ostensibly absurd segues coalesce into the most galvanizing music-history lessons—and up-to-the-minute new-schooling—imaginable. After you peep a GLK performance, witnessing a jock perfectly beat-match in one mode all night, no matter how great the track selection, will lose some of its luster. His antics and witty, vulgar pronouncements fuel audiences to outrageous levels of excitement—and it all comes off neither as pandering nor cheesy, even as he serves as his own hype man. "I always try to connect with my crowd," GLK humbly notes.

Shockingly, he can't really pinpoint the source of his greatness. "My evolution is what it is and it continues to evolve... I don't know where it comes from or where it will go next."

What can be ascertained after a few minutes of any GLK gig, though, is a superhuman energy level that's matched by extensive knowledge of (deep breath) old and new hiphop, psych rock from many nations, funk, soul, jazz, IDM, jungle, dubstep, and whatever hot-shit underground-club mutations are springing up tomorrow. The man is omni­voracious in his consumption and absorption of music, which explains why preeminent UK crate-digger Andy Votel booked GLK at his B-Music club night and enlisted him to mix All Killer, a CD compendium blending tracks from his Finders Keepers label's first 20 releases.

"It has been a blessing to run with Andy Votel and the B-music/Finders Keepers/Twisted Nerve crew," GLK says. "The music they are rereleasing and playing on a regular basis blows my mind and many minds, [and will continue to do so] for many years to come. Big up to my man Cherrystones for putting me on to so much dope music, as well. Doing [All Killer] was a blast, and I hope they ask me to mix the next 20 releases in the near future."

In interviews and onstage, GLK comes off as something of a crusader and educator for great, esoteric music, but he also attends to the more practical function of "rocking a party," with bonus articulate body language. He describes his style as "educational with a touch of rock 'n' roll energy and eclectic exorcisms. My rules, no industry standards apply."

No empty boast, that. But lest you think GLK's simply a cocky, egocentric mofo (which he is, to an extent, but justifiably so), he bestows credit to the aforementioned Low End Theory night as a turbo booster to his aesthetics and artistic growth.

"The Low End Theory is a movement," he states. "It's a place where artists can truly express their full artistic selves on and off stage. Low End Theory has more support than almost any other musical/artistic movement of its kind and of its time. It has changed me and my friends' styles a number of times over and influenced the world. I would not be the artist or the man I am without the Low End Theory."

What you will experience at a Gaslamp Killer show is a disc jockey who works strictly in CAPS LOCK mode, his expletives flying over the dopest tracks in multiple genres, slammed together with savage grace, as the most luxuriant white-boy 'fro since the MC5's Rob Tyner furiously bobs. In ways that you've never heard before, this motherfucker will kick out the jams.

This story has been updated since its original publication.