WATCH YOUR MOUTH, by Daniel Handler. St. Martin's, 232 pp.

Of all the creatures haunting the horror movie screen over the years, the golem probably had the least personality. He was, in essence, a big Jewish robot made of clay, brought to life through magic, to do his creator's will. He was especially useful in emergencies, like when violence-prone Christian peasants started getting rowdy. The stories must have been exciting to listeners in the medieval ghettos of Eastern Europe. Not to mention, reassuring. As a movie monster, however, the golem proved something of a dud -- though his awkward statue-shuffle in a classic German film of the 1920s obviously made a big impression on Boris Karloff.

The problem may have been that the golem lacked depth and charisma. He was either sexy or grotesque. And he had a very limited warranty. When the rabbi removed an amulet from around the creature's neck, he turned into dust. (At least that was what happened in a slow-paced golem movie from the '40s, if faint memories of the late-late show can be trusted.) Kind of anticlimactic, that. Not much room for sequels either.

In Daniel Handler's Watch Your Mouth, a golem stalks the Earth once more -- this time in suburban Pittsburgh and across the New Age landscape of northern California. And just like in the old stories, he is conjured up in a crisis, of sorts: The narrator discovers that a nice Jewish family is in fact a hotbed of incest. Then again, maybe not, since it is never clear that either the golem or the hyper-Freudian meltdown are quite real. Though the crisis certainly is.

If you find all that confusing...well, fair enough. Watch Your Mouth is a tricky performance, sly and willful -- and crammed with gags, many deliberately terrible, as in vaudeville. The story is drenched in sex and soggy with psychotherapeutic cliches; yet the sense of humor remains very dry. It's funny. But not ha-ha funny, so much (though that too, sometimes). More like when people say Uncle Lou is "funny," meaning you'd better keep an eye on him.

Let's see if the plot can be described without the reviewer sounding as meshuga (pardon my accent) as the narrator. Joseph, a college student, spends his summer vacation in Pittsburgh, working at a Jewish day camp for kids alongside his girlfriend, Cynthia Glass. He also keeps busy procrastinating on a term paper for a performing arts class. It's overdue because he and Cynthia spent the semester concentrating on mattress aerobics.

Settled down for the summer in Cynthia's family's house-and, to appease her grandmother, not allowed to share Cynthia's bedroom-Joseph soon finds many indications that the Glasses are carrying on like some erotic circus jointly managed by Oedipus and Caligula.

Meanwhile, the mother is also busy making props for a festival of anti-Semitic operas (ironically staged, of course, hence not offensive). Which is how she happens to be constructing a golem in the basement.

To make a long story short, the golem comes to life and kills everybody, eventually; the narrator alone survives to tell the tale. He is, as they say, "in recovery" thanks to a self-help book. Which turns out to be written by Cynthia's father. Small world!

As postmodern shaggy-dog stories go, Watch Your Mouth is plenty wacky, playing countless practical jokes on the reader. Joseph is not simply an unreliable narrator, but a very precise rendition of a 20-year old male psyche in the throes of brain-curdling libido. And he begins to tell his tale in the most overblown style of undergraduate profundity imaginable-strewing the page with extended analogies to opera, and ill-digested bits of physics, and countless purple passages, especially post-coital.

"As the house creaked around us in the cooling air," he writes, "I could feel the summer evening's consummation of the entire house. My room was above hers, my bed was above hers, and as the floorboards crackled it felt like our separate bedrooms were going to go at it with the same ferocity as their inhabitants." (Dude, that is deep.)

Then, about halfway through the book, the writing shifts from a sendup of college lit-mag pretentiousness to a strange pastiche of hardboiled detective fiction with psychobabble platitudes blended in. Several years have passed since the first golem attack. Joseph has "matured." He even suspects that all the incest business back at his girlfriend's place may have been some kind of "recovered memory." If so, then it's also possible that he is a homicidal maniac.

By the end, the golem collapses into a hardening mass of river mud, and the narrator comes to terms with his wounded inner homunculus. Or something like that.

Watch Your Mouth is a kind of 20-something follow-up to the very funny picture of high-school alienation Handler provided in his first novel, The Basic Eight, published last year. His second novel is cleverly constructed-possibly a little too much so. While succumbing to "sophomore slump," it does so with gusto -- defiantly, even: You can't imagine a more deliberate send-up of sophomoric writing. It is a weird book with an even weirder grin, like Franz Kafka on Prozac.