"The Funhouse" examplifies the contemporary horror melodrama at its least diverting and most expendable. It might have been thrown together overnight by a tax-shelter consortium calling itself Nasty, Tacky, Brutish and Tedious. Arriving last weekend at area theaters, it made "The Howling" -- certainly clever but far from foolproof -- look pretty slick.

Some providential appointment spared me the experience of Tobe Hooper's "The Texas Chainsaw Massacre" when it first sppeared, and I never worked up enough incentive to catch it on the rebound. To put it diplomatically, "The Funhouse' suggests that Hooper's flair for the horror genre was exhausted by that notorious hit. Even the key fore-shadowing speech sounds like an invitation to indifference: "You will scream with terror, you will beg for release," drones carnival barker Kevin Conway, destined to threaten four foolish youngsters with gruesome homicide when they decide to hide out in his chamber of horrors after closing hours.

The lack of conviction is supposed to be in character, of course, since he delivers the same spiel several times a day. As Hoover guides "The Funhouse" through its listless, perfunctory motions, it's difficult to resist the impression that the filmmaker himself is short on enthusiasm for this particular round of boogie-boogie-boogie.

"The Funhouse" begins with a lamely facetious reprise of the shower sequence from "Psycho" and slides steadily downhill there. Apart from a climatic sequence of bravura lighting and editing in which the heroine eludes the grasp of a homicidal fiend -- while simultaneously bedeviled by a dangling power line and caught between giant circular gears -- the level of terrifying provocation is more pedestrian than sensational. Even then the heroine acts idiotically inclined to stay within reach of the sizzling, mangled beast.

The entrapped teenagers not only go out of their way to place themselves in peril but also behave in such a stupidly amoral fashion that they virtually beg to be knocked off. After playfully deciding to spend the night in the funhouse attic -- couriously envisioned as a kicky place for erotic recreation -- a set of double-daters witnesses the murder of the carnival fortune-teller, a whorey crone impersonated by Sylvia Miles, at the hands of Conway's unfortunate, uncouth progeny, a young monstrosity whose Frankenstein mask conceals an even less comedy natural visage.

Perhaps it's forgivable for sheer conveniece's sake that the merry make-outers should overlook the most obvious exit after watching the killing -- through the door of the victim's quarters. However, it seems quite unforgivable that one of the boys should take the opportunity to rob the victim. Far from seeking plausible escape routes, the witnesses make a point of encouraging further homicide, on the theory that it's too late to seek assistance from the law, or even the law-abiding carny folks who appear to be within earshot.

"We'll just have to wait for them to make the first move," comments the heroine's fast-thinking hunky date. This line of argument may be convenient for lazy filmmakers, but horror freaks who care enough to discriminate between attractions could make the first smart move by giving "The Funhouse" a prompt pass.