It’s appropriate that the first sign of paranormal activity experienced by the Taylor family in their suburban home is a bad odor, because “The Darkness,” the horror movie by Greg McLean in which their story is told, is a stinker. Australian McLean is appreciated among genre aficionados for his grisly shocker “Wolf Creek” and its sequel, but this misfire will win him more notoriety than renown even among his fans. It should never have seen the light of day.

Essentially “The Darkness” is just a haunted house movie, reminiscent of “Poltergeist,” but with a distinctly Southwestern twist. The source of the trouble is a trip the family—Peter (Kevin Bacon) and Bronny (Radha Mitchell), along with their children, teen Stephanie (Lucy Fry) and adolescent Michael (David Mazouz)—take to the Grand Canyon and its environs. During a stopover near some scenic cliffs, Michael—who’s autistic (one of the more tasteless elements of the plot is a supposed connection between autism and the spirit world)—discovers five odd rocks in a hidden cave, which he secretly brings home in his backpack. These will release demons once confined in them by Anasazi priests—entities that come forth from the seething wall of the boy’s room as “shadow creatures” eventually assuming animal form.

The evil spirits naturally have a malignant effect on the family members. Workaholic Peter is tempted to have an affair with a young aide. Bronny, apparently a recovering alcoholic, takes to purchasing multiple bottles of vodka. Stephanie goes bonkers when her mother discovers that she’s bulimic. And Michael, of course, becomes increasingly mesmerized by his visions, which threaten to carry him off to the shadow world (a fate, it’s suggested, that often befalls autistic youngsters who fall prey to such demonic influences).

Fortunately Peter’s boss (Paul Reiser, bellowing out his lines with unaccustomed ferocity) learns of the family’s plight and suggests that they contact an exorcist named Teresa (Alma Martinez), who promptly arrives with her granddaughter Gloria (Ilza Rosario) to cleanse the house. This leads to an orgy of mediocre visual effects, culminating in a loony scene in which Peter and Michael demonstrate their love for each other by working together to close the door to the shadow world that’s opened in the boy’s room and threatens to swallow him up. (Luckily the demons’ lair is the very cave where Michael found the stones, whose replacement in their original places now turns off their invasion of the Taylor abode.)

Even if it were well made, “The Darkness” would be a sadly derivative piece whose additions to the “Poltergeist” template are both confusing and insensitive. (Michael, for example, is first contacted by a seductive spirit he calls Jenny, whose identity is never explained.) But it isn’t. Toby Oliver’s cinematography is terrible, mostly consisting of herky-jerky handheld shots and washed-out images (a concession, perhaps, to the poor effects with which the live material must coexist). And it’s worsened by Sam Lahiff’s chaotic editing: some sequences, like a dog attack on Stephanie, are completely muddled, and loose ends abound.

The real villain, however, isn’t any demon but director McLean, who seems unable to stage scenes properly or encourage his cast to do their best. Bacon brings his usual intensity to the tormented father, but is defeated by the character’s vague motivations, and Mitchell is similarly stymied. Fry, like Reiser, is too often instructed to play things in manic style, while Mazouz adopts a mostly blank pose, his stare only occasionally interrupted by a smile or brief outburst. (The fact that the movie has been on the shelf for a while, incidentally, is evidenced by the fact that he looks considerably younger than he does in his role as Bruce Wayne on “Gotham.”)

In sum, this is the sort of schlocky mess that gives horror movies a bad name. The only thing that might help it would be to remove the bulb from the projector; real darkness would be scarier than McLean’s variety.