He grabs the microphone, shimmies back and forth like an out-of-control veg-o-matic, sticks his head into the bass drum, falls to the floor, bites a back-up singer on the thigh and breaks into a slow blues. "The Heart-break of Psoriasis."

He blacks out the letter "F" on a box of "Froot Loops" cereal and tosses "roots Loops" to the audience.

Rows of people stand on their seats in a Baltimore auditorium and heckle him.

Someone picks up an ashtray and hurls it onto the stage, missing his head by a hair.

Two women from the audience join him on stage and dance, topless, to the tune of "Christmas At K-Mart."

You have to love it or leave it - and may patrons choose the later. But unlikely as it seems, Root Boy Slim, of Washington's own "Root Boy Slim and The Sex Change Band" (featuring "The Rootettes") may have a good chance of hitting big time. Last night talent scouts from three record companies were flying from Los Angeles and New York to catch his act at The Childe Harold. And his local fans - a growing legion, mostly byword of mouth so far - were expected out in force. So this particular brand of inspired madness may yet bring fortune and fame.

He is not to say the least without his detractors. Some people say he's just a fad, some say he's silly, some think he won't last another month.

To which Root Boy smiles and says "I'm a late bloomer."

Root Boy Slim was born Foster "Ken" McKenzie 33 years ago the son of a golf course architect. He grew up in Washington, went to private schools, graduated from Yale. There he met Bob Greenlee, new the bass player for "The Sex Change Band" and co-author of Root Boy's material. The two formed a band at school and covered the East Coast college circuit, playing at fraternity parties in shark sking tuxedos. Prince La La and The Midnight Creepers," as the band was known, had the dubious distinction of never playing the same place twice, Greenlee tells the story of playing the Vassar prom one year. One of the hand members threw up during the prom queen crowing ceremony.

"We used to rip the tuxedos all each other" says Greehlee . "Root Boy used to dive into the audience for his final. There was nothing but chaos on the stage. We didn't take it too seriously."

After a year of graduate school, (McKenzie studied urban planning at American University, which he says "totally qualities me to sing the blues"). Greenlee and McKenzie drifted apart. But they joined forces again in Florida where Greenlee was putting together a band. They came to Washington last [WORD ILLEGIBLE] where McK*enzie met Joe [WORD ILLEGIBLE] of Maryland, Acting Gov. Blair Lee and they decided to put on a show.

Lee and local artist Richard Banham produced a 13-song tape at Silver Spring's Track Studio, which they hope will snag Root Boy his sought after recording contract.

Offstage, McKenzie is unexpectedly quiet, even shy. One expects to be zapped between the eyes with one liners and finds, instead, an artist who talks knowledgeably about his craft. There are, however, light moments.

McKenzie says they never rehearse and he and Greenlee remember the night at the Psyche Delly in Bethesda when Root Boy ended up throwing beets at the audience.

"They weren't on the beat," says Root Boy. "Get on the beat," I told them.

Another reason for the orginality of the show may be Root Boy's poor memory for lyries. Greenlee is often spotted mouthing words for his benefit. But a lot of their work is umprovisational. I wrote, "You Broke My Mood Ring on stage one night in a bag full of hookers," Root Boy Says.

"Jail in Jackonsville," recounts Root Boy's brief incarceration there. And then there's "Too Sick to Reaggae," in which Root Boy lands in Montego Ball jail, having been arrested for posession of marilunea. "Bride of the Burro" is described as a "Tijunna toll tale in the manner of John Lug Hooker."

Most of Root Boy's fans tend to be older than the usual rock crowd, and one of the band's most popular numbers is "I'm Not Too Old For You," their answer to the '50s, "Born Too Late." root Boy arches a lecherou-eyebrow and moans," "You're 17 and I'm 32. I'm Not Too Old For You. The Rootettes two vamp-like back up singers who [WORD ILLEGIBLE] their hips. Insp. their lips and chew gum at the same time, echo the phrase with nonchalance. He's not too old for you.

Root Boy Slim and The Sex Change Bank may indeed be ahead of their time. Dressed in a silver and black cape and huge silver sunglasses that spell "Root." McKenzie looks like James Brown in "Star Wars."

"Ahead of out tone? Who Knows. We don't even know what time it is," says Root Boy Slim.

"This is a prophetle show," concludes Greenlee philosophically. The apocalypse of rock in roll."