ALERT VIEWER WHAT PLANET ARE YOU FROM? Comic fable. Starring Garry Shandling and Annette Bening. Directed by Mike Nichols. (Rated R. 100 minutes. At Bay Area theaters.)

Garry Shandling is a pathetic imitation of a human being -- a clueless, sex-driven male, which is exactly what he's supposed to be in "What Planet Are You From?"

In this comic fable directed by Mike Nichols, Shandling plays an extraterrestrial sent to impregnate an Earth woman and begin a takeover of this planet, a form of boring from within. The humor goes from extremes of dirty-old-man blatancy to the offhand and subtle. It's good for a few guffaws and chuckles, but in between the screen has a tendency to stretch at the corners and go flat.

Portentous title music accompanies a Voice of Doom announcer who explains there is only one little problem with the takeover from outer space. This male-only civilization is so advanced that its citizens' reproductive organs have shrunk. Shandling, equipped with an attachable penis and an Earth name, Harold, has two days to get a woman pregnant.

The carbon-copy men in this highly evolved society sit in rigid tiers, just like movie-multiplex audiences in stadium seating, and get lectures on how to seduce women, or at least a hologram of one. (Compliment them on their shoes. Tell them they smell nice.) These men are minimalist everything, from their clothes to their emotions. Harold will tell strange women they smell nice but avoids intimate situations.

Annette Bening pulls off a neat surprise. Playing the flip side of her role in "American Beauty," she makes this comedy unexpectedly touching, as a Phoenix real estate agent and recovering alcoholic. She approaches this alien male who wants to have a baby with complete, if misplaced, sincerity. She has the habit of picking the wrong man and does it again when she marries Harold. The audience will blink twice when Bening sings an off-the-wall version of "High Hopes."

In this movie variation on "Men Are From Mars, Women Are From Venus," male earthlings also tend to be pathetic imitations of human beings. Greg Kinnear, with a goatee, plays a randy banker who is such a louse that he goes to AA meetings only to pick up women. John Goodman, as an FAA investigator looking into Harold's sudden materialization on an airliner, at first seems to talk to his neglected wife only by phone.

When Harold gets an erection, it makes what on several occasions is described as a humming noise. Actually, this humdinger sounds more like a spring unwind ing. The upside is that Harold has remarkable staying power -- 21 hours on his wedding night. Also, it vibrates.

The tan, preternaturally gleaming-toothed but nonetheless doughy Shandling gives Harold a smarmy delivery frequently accompanied by a pained smile. Shandling's "thoughtful" timing was typical of his TV shows -- the characters take time to absorb things and think before they speak -- but leaves an awful lot of air around it on the big screen. It pays off in small moments, as when Kinnear tells him, "You're only human."

"What Planet Are You From?" finally settles into a rather sweet fable about sincerity, quite a subject in an era that prizes irony.

Janeane Garofalo comes and goes in a cameo that does not register at all, and it was beginning to look as though Linda Fiorentino, as the roving banker's wife, would have a similar fate. However, Fiorentino gets, and hits out of the ballpark, the movie's single funniest line. ..