From live rats to a demented clown, this is no ordinary haunted house

NEW YORK -- You'll never sleep well again.

That come-on line is meant to lure Halloween-minded adults to "Nightmare" -- 13 high-tech Manhattan rooms filled with terror. And it's so ghastly that no one under 16 is admitted without a guardian.

The gimmick is to walk spectators from one room to another, sometimes through dank, narrow passages, as they face hair-raising scenes. Sprinkled with fake blood and real curses, the rooms feature live rats (behind plexiglass), a demented clown, and a little girl who disappears under her bed, among other alarming encounters.

This sophisticated haunted house was created on a $200,000 budget by the Psycho Clan -- four producers working with a group of young visual and theater artists who play off human fears with an edgy downtown twist. Each artist assaults viewers' senses with scenes that are all too real.

Without giving away the gag, it all starts with something wet, warm and fleshy, flying at you in the dark.

Ever been buried alive? Here's a chance to try.

How about the ferocious barking dog that's about to bite your ankle -- but you don't know where it is.

The Clan thinks its haunted house is so scary that they issued a warning: The show is not recommended for those with heart problems, or anyone prone to seizures or afflicted with clinical anxiety. Once you're in, you can't leave.

"When you're trying to get this kind of reaction from an audience, you're afraid you might actually get it," said Timothy Haskell, an Off-Broadway director who leads the Psycho Clan.

In short, he says, it's "an adrenaline fix."

"About a dozen people threw around ideas for months. We had hundreds of them, then whittled them down to the 13," said Haskell, 31, a native of Atlanta. "That was the really fun part. There were some sick, really sick ideas."

More David Lynch than John Carpenter -- that is, more witty and weird than straight-on shock -- the 30-minute "Nightmare" is staged on a 9,000-square-foot floor of the Clemente Soto Velez Cultural Center on Manhattan's Lower East Side. The plan is to usher through small groups at three-minute intervals.

It costs $20 ($15 for accompanied 16-year-olds and under) to get the chills that began Friday, running through 2 a.m.; the last show plays on Halloween night. For younger kids, a PG-13 version is offered on weekend afternoons.

It's not easy to scare New Yorkers, who already face a daily array of freakish encounters. Still, the creators promise that "from psychoses to neuroses, this house of horrors will haunt your dreams. You'll never sleep well again."