Not since Audrey II took root many full moons ago has there been a bloodsucking musical-comedy creation as endearingly voracious as Edgar, the boy descended from a bat.

Audrey II, you may recall, was the jiving houseplant hooked on red corpuscles in "Little Shop of Horrors," the campy pop musical that made delicious sport of Hollywood splatterfests. Now comes Edgar, Audrey II's theatrical descendant, to send tingles up the spines of the tormented denizens of Hope Falls, W.Va., in "Bat Boy: The Musical," a silly, raucous, shameless spoof sprinkled liberally with sophomoric mayhem -- and yes, even a bit of wit.

"Bat Boy," by a trio of young Los Angeles writers -- Laurence O'Keefe supplied the score and Keythe Farley and Brian Flemming collaborated on the book -- is not quite in "Little Shop's" league; the show goes on long after the joke has worn out. But if you're in the right frame of mind -- in other words, if smarty-alecky, college-level antics don't send you rummaging for the Advil -- "Bat Boy" might be an amusing night out.

The production at Studio Theatre Secondstage has one especially useful secret weapon: its young star, Patrick O'Neill, who with any luck is going places. Fitted with Mr. Spock's ears and a pair of canines that would do Bela Lugosi proud, he makes for a puckishly entertaining cave dweller. For if there is one attribute a kid with prominent fangs must possess in the loony world that "Bat Boy" inhabits, it's the ability to carry a tune. Indeed, O'Neill proves himself an agile, old-style song-and-dance man; imagine, if you will, Mickey Rooney as the product of a botched 4-H Club experiment.

It's also essential in desiccated Hope Falls -- a town so pathetic that it can't keep its cows from dropping dead -- to hang on to one's sense of irony. Like its satirical cousin "Urinetown," the Broadway hit about a city and the corrupt company that controls its urinals, "Bat Boy" is a sendup of musical theater itself. We know, for instance, that it's only in musical comedy land that a half-boy, half-beast would make his first human sounds to the strains of a Broadway-style ballad. Or that the girl who falls for him in spite of (because of?) his blood lust would offer the declaration in song: "Come spend your life on my arm."

The story, apparently lifted from the pages of a supermarket tabloid detailing the purported discovery of a feral boy living in a cave, gives the writers of "Bat Boy" license to poke fun at all sorts of pop and serious culture, from the joys of junk food to the work of Stephen Sondheim. The plot is an inane smorgasbord involving, among other things, a mad scientist, a slaughterhouse, a revival meeting and the god Pan. Some of this is painfully over the top -- the scenes elucidating the townspeople's worries about their dying cows are particularly tiresome -- and all of it unnecessarily elongated; it feels as if Bat Boy is singing about his desire for acceptance every 10 minutes or so.

Yet "Bat Boy" does deliver the goods now and then, particularly in the middle part of the tale, when O'Neill makes the transition from uttering pitiful squeaks to declaiming like a member of the Royal Shakespeare Company. (He listens to BBC language tapes.) In a number cleverly staged by director Mike Chamberlin, the boy's foster mother (Lauri Kraft) uses flashcards to teach him world landmarks, an exercise that leads to a breathless litany: "Pentagon, Amazon, Taj Mahal, Wailing Wall." And the second act starts off rousingly, with an ebullient gospel song performed with gusto by Carlos Offutt.

The 10-member cast has the requisite spirit, and the unfinished space the show inhabits, in a building adjacent to the main Studio Theatre complex, feels like an appropriate home for a piece with such raw energy. Among the players, Tara Giordano is especially good as Bat Boy's teenage romantic interest; she gets the mocking, self-important tone just right, and she can sing the role, too. (A few of her colleagues have pitch problems with the demanding rock-and-roll score.)

John Raley, the set designer, comes up with some aptly tacky sight gags: The chiller-theater reenactments of Bat Boy's origins from behind a screen remind you of fright night at the drive-in. But it's O'Neill's slithering Bat Boy, creepy and charming at once, who leads this juvenile romp out of the darkness.

Bat Boy: The Musical. Music and lyrics by Laurence O'Keefe, book by Keythe Farley and Brian Flemming. Directed by Mike Chamberlin. Sets, John Raley; choreography, Michael J. Bobbitt; lighting, Colin K. Bills; costumes, Michele Reisch. With Buzz Mauro, Kate Debelack, Mark Bush, Terry Crummitt, Meghan Touey and Doug Sanford. Approximately 2 1/2 hours. Through Dec. 8 at Studio Theatre Secondstage, 14th and P streets NW. Call 202-332-3300 or visit www.studiotheatre.org

Patrick O'Neill as Edgar the Bat Boy and Tara Giordano as his girl in a musical-theater sendup ripped from the tabloid headlines.