"The Entity" may be the least catchy title in movie history, and for the first tedious hour or so this curiously indecisive account of supernatural sexual intimidation remains in an expedient and exasperating rut: writer Frank DeFelitta and director Sidney Furie seem fixated on the rape scene from "Rosemary's Baby." The fixation takes a myopic form, with Furie insisting on an underlit but skintight vantage point as Barbara Hershey, cast as Carla Morgan, a single mother struggling to support three kids in a rented house in Los Angeles, is repeatedly attacked--in bedroom, bathtub, living room and even automobile--by some ferocious, invisible molester, or maybe molesters, from the spirit world.

The deliberately murky, close-up compositions suggest that the camera must be set up in the strands of hair along the leading lady's ears. Not content with this extreme pictorial affectation, Furie also keeps the frames tilted, forcing you to adjust the angle of your head while squinting and peering in the ultra-intimate gloom. "The Entity" appears to be a one-track exploitation movie, dedicated to reaching feature length by contriving variations on the solitary theme of Barbara Hershey at the mercy of phantom assailants.

Ron Silver, cast as Dr. Sneiderman, a friendly analyst who assumes that Carla is the victim of some kind of hysterical delusions, is called upon to do the bulk of the acting and expository talking for the show, and while he's certainly well-qualified to handle the load, you can't help feeling as if the heroine is being curiously deprived of the opportunity to articulate her own unique, perilous crisis.

Suddenly "Poltergeist" becomes a stronger influence than "Rosemary's Baby," and the switch generates some melodramatic momentum and suspense. Carla's tormentors do enough damage to corroborate her testimony, at least in the estimation of moviegoers and a team of parapsychologists though not the psychiatric fraternity, which DeFelitta rigs for scapegoat duty. During one attack Carla's teen-age son is injured, and during another the house of a friend is demolished while Carla seeks refuge there, with the friend handy enough to witness the unholy uproar with her own astonished eyes.

The presence of a green-hued magnetic sex fiend from The Other Side is verified when the parapsychologists set up their equipment in Carla's house. They propose to bring it back alive by arranging an elaborate, enjoyably farfetched entrapment scheme that involves luring the spirit to a lab mock-up of the house fabricated in a college gym, directing Carla to an isolation chamber as soon as it threatens to attack and then bombarding the intruder with liquid helium, which will theoretically freeze it to the spot. Meanwhile, Dr. Sneiderman has cultivated a romantic interest in his former patient and can't help trying to protect her from people he regards as dangerous scientific crackpots even after Carla tells him to get lost.

Between the preparations for the climactic ghost-nabbing and Sneiderman's lovelorn interference, "The Entity" works up some effective steam down the stretch, only to squander it when the chips are down by playing now-we-have-it-now-we-don't with the spirit when it ventures within firing range of the helium compressers.

"The Entity" bows out on a lame epilogue. Although the filmmakers seem to have botched the payoff to their slow-to-develop story, they insist that it's okay, because that's what happened to the real-life prototype for Carla Moran, who moved to Texas, where she still experiences the occasional visitation. A note like this makes it rather difficult to know whether the preceding narrative was meant to carry any weight at all.

Was Carla part of a decisive episode in the annals of the supernatural or just being warmed up for a main event? If there's more to be told about such a beleaguered heroine, it really won't do to tack on such perplexing updates right before inconclusive fadeouts.