Did Stephen King have an unhappy childhood, or what? If he did, no unhappy childhood ever turned so handsome a profit.

Many of King's stories, at least among those that have been filmed, depend for their thrills on imperiled or bedeviled kids -- children as victims or villains -- and depict childhood as a hellish nightmare. In "Cujo," a gasping little boy is menaced by a rabid St. Bernard. In the sick, sordid "Pet Sematary,"

a child is run over by a truck, then returns

from the dead to murder its mother and bite an

old man's jugular.

"Children of the Corn" was about a satanic kiddie cult, and in the anthology film "Cat's Eye," a little girl is preyed upon by a rat-sized fiend.

Now comes "Stephen King's 'It,' " a two-part, four-hour ABC "novel for television" airing tomorrow and Tuesday at 9 p.m. on Channel 7. In this one, King unleashes a grisly monster who lives in the sewers of Derry, Maine, and delights in luring children to their deaths. One little boy gets his arm ripped off by the demon, we are told; the body of a little girl, says a TV newscaster, was found "severely mutilated."

Whose idea of fun is this? King brings new meaning to the phrase "exploitation of children."

The miniseries has been in the works for years at ABC, which kept announcing and then postponing "It." Parents attempting to calm frightened children who see the show -- and develop an unnatural fear of plumbing, from which the evil beastie attacks -- may well wish it had been postponed forever.

On the other hand, adults yearning for a good jolt will be disappointed to discover that while the film has its affecting elements (most of them recalling scenes from "Stand by Me," a non-horror film from another King tome), last week's episode of "Twin Peaks" was much more persuasively scary.

Try as director Tommy Lee Wallace does, he just cannot turn colorful circus balloons into chilling instruments of terror. The balloons are meted out as portentous calling cards by a demonic clown called Pennywise who is the monster's chief manifestation. Tim Curry of "The Rocky Horror Picture Show" plays the clown, gleefully flashing icky pointed fangs and what looks like a bad case of gingivitis.

Part 1 introduces the seven children who band together in 1960 for the purpose of destroying the festering evil that lurks beneath weary dreary Derry. Then, in Part 2, six of the seven regroup as adults when they are summoned to do battle with the monster, dormant for 30 years but now up to his foul tricks again.

What do the other Derryians do? Nothing. They are paralyzed with fear and apathy. "It" is sort of a parable about how evils like fascism and racism can grow when fed by indifference and timidity. But the metaphors never quite jell.

"I'm everything you were ever afraid of," the killer clown tells the children, and it's suggested he represents private demons that must be exorcised in addition to his role as a public nuisance. This isn't a very original idea however -- the monster assuming custom-made forms tailored to individual anxieties. Other forms he assumes include a werewolf, a giant spider and a fortune cookie with an eyeball in it.

Yes, really. What will these monsters think of next?

Some of what was meant to be heart-pounding is rib-tickling, as when the pasty, disembodied head of Richard Masur, as one of the Derry-dwellers, appears in a refrigerator to spew invective and hurl venom -- or is it the other way around? The cast also includes John Ritter, Dennis Christopher and Richard Thomas (who plays a horror novelist not unlike King), with Tim Reid and Annette O'Toole doing the best jobs of maintaining dignity, and the consistently unwelcome Harry Anderson doing the worst.

Jonathan Brandis, who plays Ritter as a child, manages an impressive credibility, considering the context. As kids, the little band of misfits names itself the Loser's Club and gets picked on by everyone, including a sadistic daddy and a vicious, knife-wielding bully.

Whatever the intermittent shocks along the way, the net effect is nil. "It" is just one of those things.