Castro, the rap star protagonist of Alonzo D. Lamont Jr.'s provocative new play "Vivisections From the Blown Mind," which opened Wednesday at Arena Stage's Old Vat Room, is at first glance a man at the very apex of his profession. "The hottest entertainer in the world," he commands outrageous fees, appears in outrageous action flicks, sports an outrageous wardrobe, spews forth outrageous answers at press conferences that are instantly turned into fodder for his adoring fans. But though Castro keeps reminding himself and his entourage that he's got "the bucks, the beat, the banks, the babes and the business," it doesn't take long to figure out that this shooting star is going down fast.

Lounging in his Hollywood spa with his agent-lover, Angelique, ordering his "homeboy" Dusty to fetch "liquids," Castro (Lee Simon Jr.) fluctuates between swagger and insecurity. Angelique, played by Katrina Van Duyn, whom he refers to as either "Blonde" or "Mommy," is clearly worried about her client; at the press conference held earlier that day, he pulled out a gun and pointed it at the crowd and his own head. And when, lolling in his hot tub, he pushes her roughly under the water and then attempts to drown himself, we know there's some deep dark problem, some secret past just waiting to be revealed.

To his credit, Lamont does not present things in standard melodramatic terms. By means of a brilliantly written and performed monologue about Castro's experiences on his latest film shoot, we learn that "I didn't fit. All I could feel was me going in reverse -- going some kind of backwards." In attempting to reproduce his "signature moment" over and over in front of the cameras -- wielding a .45 Magnum and exclaiming "I ain't be dead, now eat lead!" -- he realizes that he has become a caricature, a shill, just another black entertainer with a sure-fire gimmick. Having created a persona from the ground up, Castro has gradually lost all sense of self.

Lamont's on-target awareness of rap's power as both a political tool and a shallow but hypnotic crowd-pleaser is dramatized most effectively in Act 2. During an interview with ace journalist ("Ace of Spades," jokes Castro) Goliath Ardsberry (a smooth-as-silk Vincent Brown), the star finds himself confronted by a host of demons. Afer a few bottles of bubbly have been consumed, Goliath proceeds to cut through Castro's brash, foul-mouthed exterior and to question his motives. And then, in yet another highly evocative monologue, the reporter -- soft-shoeing like some tipsy Bojangles Robinson -- delivers a mini history lesson on those he perceives to be the real movers and shakers of black culture: Bessie Smith, Thelonious Monk, Adam Clayton Powell and Martin Luther King Jr. Clearly, Castro's chosen form of expression has no place in the suave, solidly middle-class Goliath's pantheon of greatness. By the end of the scene, the rap masterhas cracked and violence has been committed. But the starmaking machinery continues to grind on relentlessly.

This is a dynamite production in many respects. Director Clinton Turner Davis has turned the stage into a land mine, a place where every word, look or gesture is a potential weapon. He's aided immeasurably by set designer Michael Franklin-White's glitzy spa and living room (the hot tub is most impressive!) and Betty Siegel's up-to-the-minute costumes. And with the exception of the mannered, unconvincing Van Duyn, his cast brings a difficult script to vivid life.

Simon's portrayal of Castro is multilayered and electric. He's got the physical presence and verbal deftness of a feisty pop star, and also an intelligent, brooding quality that serves him well during the play's most disturbing moments. M.E. Hart plays the sidekick-servant Dusty with just the right mixture of playfulness and concern. Most memorable of all is Brown's Goliath, a nattily dressed, supremely confident man whose gentrified "rap" is every bit as compelling as Castro's.

As is probably apparent by now, "Vivisections From the Blown Mind" is definitely not a mainstream drama. Chock-full of profanity and street talk, it presents its subject in complex, uncompromising terms that may rattle or perplex even the most open-minded spectators. And, much like Elia Kazan's '50s film "A Face in the Crowd" -- the saga of a megalomaniacal hillbilly singer who makes it big and crashes hard -- the play's chilly landscape and cast of unsavory characters make it hard to respond in an emotional fashion. But Lord, does Lamont make us stop and think.

Vivisections From the Blown Mind, by Alonzo D. Lamont Jr. Directed by Clinton Turner Davis. Set, Michael Franklin-White; costumes, Betty Siegel; lighting, Christopher V. Lewton; sound, Celeste A-Re. With Lee Simon Jr., Katrina Van Duyn, M.E. Hart, Vincent Brown. Through May 26, Arena's Old Vat Room.