From the intergalactic hatching of Ziggy Stardust to Garth Brooks's transformation into bewigged goth-rocker Chris Gaines, musicians have long been inspired to feats of daring, genius, and hilarious failure by the lure of the alternate persona. In the best cases, such alter egos give established artists a fresh way to fuck with their audience and their own celebrity (see the various gender- and species-bending personas of David Bowie). In the worst cases, such role-playing feels like rock-star Halloween crossed with an improv exercise at which audiences are forbidden to laugh (see the aforementioned Chris Gaines, which reigned as the funniest thing Americans were not supposed to laugh at until Dick Cheney shot that guy in the face).

Last year brought two new entrants onto the alternate-persona playfield, one major, one minor, both announced via cryptic viral marketing. "Who is William Control?" asked glossy posters wheat-pasted around my Central District neighborhood last autumn. "Who is Sasha Fierce?" asked shimmering banner ads placed on several well-trafficked websites last winter.

The William Control question was accompanied by a photo of what looked like an adolescent mime in smudgy eyeliner smoking a cigarette. The lack of context and expectation of recognition led me to guess that young Mr. Control—who bore a distinct whiff of the Joker—was the latest fey diabolical comic-book-villain type.

I was wrong. William Control is the musical alter ego of Seattle musician Wil Francis, lead singer of Aiden, the "darkwave"/screamo outfit that's reportedly huge in Europe and that I'd literally never heard of until this ad campaign. Investigation revealed Aiden to be purveyors of that type of derivative posture-rock that can only be truly intoxicating to those younger than the band's members; anyone older than Aiden who might appreciate what the band have to offer should already be fully saturated with the work of the 101 equally derivative pop-punk bands Aiden are scavenging for parts. As for William Control, he seems to be Francis's effete cousin, with a fondness for ascots and synthy new wave. It's a step up musically, at least, with William Control's techno leanings allowing a melodic goofiness banished from Aiden's world of machine-gun guitar and Cookie Monster vocals. But the lyrical content remains strictly limited. “I’ll never love again,” sings the pale young man in the velveteen blazer and white face paint, in his song “Beautiful Loser.” With laughter an unacceptable response, I must turn away.

Which brings us to Sasha Fierce, whose instigating question—"Who is Sasha Fierce?"—was answered by a Herculean PR blitz informing the public that Sasha Fierce is the imaginary alter ego of the one and only Beyoncé Knowles, who was now releasing her third solo album, I Am... Sasha Fierce. It was a double-CD set with one disc credited to Beyoncé—leader of the best-selling female group of all time™, blockbuster solo artist, movie star, and wife of Jay-Z—and the other attributed to Sasha Fierce, an alter ego Beyoncé reportedly birthed during the video shoot for "Crazy in Love," which required the singer to shake her booty in silhouette in some of the shortest shorts ever to bear the name, over the song that would make her a superstar. The two CDs are meant to symbolize the two halves of Beyoncé—one the real-life woman with real-life feelings, the other the professional entertainer who'll do astounding things to entertain us.

Had I Am... Sasha Fierce carried out this real-life/art-life split—offering, say, one CD of Sasha Fierce belting out amazing pop songs and another of real-life Beyoncé pooping and arguing on the phone—the result might have been worth paying attention to. But what Beyoncé calls "alter egos," most people call "moods," and the double-life shtick is a dead end. What's most galling about I Am... Sasha Fierce's failure is the stupidity of the whole endeavor. Beloved by millions the world over for who she is, Beyoncé chose to relegate her most interesting traits to some invented other—the exact inverse of what smarter musicians have been doing for generations. To wit: Talking Heads did not rename themselves "Mr. Big Suit and the Accumulating Band" for Stop Making Sense; they blew people's minds by showing how freaky and artsy Talking Heads could be.

In the end, the richest motive for creating an alter ego remains the basest: to fuck with people's heads. And in this regard, Kool Keith is the eternal master. After introducing himself on Ultramagnetic MC's classic Critical Beatdown, Keith Thornton set about amassing a stable of alter egos now numbering in the dozens, among which reside a small handful of "major" characters—Dr. Octagon, Black Elvis, Dr. Dooom—who routinely fight and kill and resurrect each other, existing primarily to illustrate what a uniquely insane bad-ass Kool Keith is. Major characters come with bios ("Dr. Octagon is an extraterrestrial time-traveling gynecologist and surgeon from the planet Jupiter") and give interviews. As Reverend Tom—Kool Keith's alter ego in Thee Undatakerz—he told a journalist in 2003, "It's better to morph than to stay who and what I am, because if I was to stay that way, then your government wouldn't allow me to be here any longer."

The morphing continues, in all directions: While various websites (including Keith's own) hype the imminent arrival of Tashan Dorrsett, a new Kool Keith character described as a "real and regular person from New York City," this week's Neumos show is credited to Dr. Dooom vs. Dr. Octagon aka Kool Keith. God knows what that means, but prepare for a most entertaining mindfuck.