If "Demos Seed" and "Adurey Rose" weren't intended as companion features, they should have been. The former, a science-fiction mutation on the devil-child thrillers, tends to confirm the suspicion that Hollywood harbors some animus toward ordinary children and perhaps ordinary life processes, since the picture ends up endorsing crossbreeding between computers and humans. "Audrey Rose," which opened Friday at three area theaters, makes an equally feckless case for reincarnation by insisting that a character likely to impress audiences as a child molester is a spiritual benefactor.

Most of the miscalculations that transform "Audrey Rose" into a potential laughing stock seem to have originated with Frank De Felitta, who fashioned the screenplay from his own novel, inspired by an incident that led him to Edgar Cayce, India and an apparently slaphappy belief in the immortality of the soul.

The incident that transfixed De Felitta was rather beguiling: his six-year-old son, who couldn't play the piano and can't play it now, supposedly sat down one afternoon and began tickling the ivories in the style of Fats Waller. Perhaps someone should have encouraged De Felitta to write a comic fantasy about a little kid who plays like Fats Waller. The psychic mysteries and spectacles arranged for "Audrey Rose" are conspicuously unbeguiling. Trying to whip audiences into a hysterical frenzy with the sight of a tormented child and then exorcising that distress with blithe assurances of immortality, De Felitta looks profoundly inept and foolish.

Marsha Mason and John Beck are mired in the miserable roles of Janice and Bill Templeton, a contended, prosperous New York couple suddenly unhinged by a stranger named Hoover, played by dead-eyed Anthony Hopkins, who insists that their bubby 11-year-old, Ivy (Susan Swift), is thereincarnation of his daughter Audrey Rose, who perished 11 years earlier in a fiery car crash.

The premise would stand a chance if the writer shared the suspicion such a fanastic interloper is bound to inspire in the audience, particularly when played by a specialist in furtive behavior like Hopkins. The character of Hoover needs some ambiguity, in the tradition of Miss Jessup in "The Turn of the Screw" and the psychic charlatan played by Joel Grey in "Man on a Swing." De Fellita is so partial to Hoover that he ends up treating the Templetons' objections as so much pathetic middle-class fussiness, depriving the story of credibility and suspense. Incredibly, the parents are expected to be grateful that a stranger has taken away their only child, body and soul.

"Audrey Rose" invites ridicule from the first glimpse of shabby, beared Hopkins lurking around Ivy's school. An eyesore this blantant would have spooked the whole block, but we're evidently supposed to believe that Mrs. Templeton is the first one who notices him and finds him a little weird.

By the time De Fellita builds to a memorably nutty courtroom case in which Hoover is allowed to "prove" that Audrey Rose is lurking inside poor Ivy, one is ready to throw the case out of court and hoot the movie off the screen. Couldn't anyone have anticipated the obvious objections to such a wrongheaded conception? Frank De Fellita has ever written a popular movie, but director Robert Wise has been associated with several.

He - or someone in authority - should have had enough savvy to perceive that creepy-crawly Hoover is the last character in this story people are going to identify with.