ORLANDO -- If you think Universal Studios' Halloween Horror Nights is just another haunted house, you need to get out of your coffin more often.

''Rrrrrrrrr,'' sputters a chain saw, just inches from your back.

''Ha-ha-ha-ha-ha,'' cackles the Wicked Witch of the West, who has taken over the former Plaza of the Stars and brought those nasty monkeys with her.

Ghouls and goblins hiding in the jack-o-lantern patch jump right in your face, and the demented creatures from Alice's oh-so-warped looking glass chase you through smoke and mist.

And that's just in the streets. Add in eight houses of horror, three Halloween themed-shows and five regular scary rides open during the evening event, and you can understand why hundreds of thousands of guests are expected to turn up during the 23 nights of this, the 18th annual Halloween Horror Nights.

SPECIAL TRIP

Charles McClure, an American who lives in Ireland, times an annual business trip to the United States to coincide with one of the fright nights. This was his fifth visit with his kids, ages 15-21. ''I love watching the kids get the crap scared out of them,'' he said. ``It's great, clean fun.''

Make that PG-13 fun. Even Universal's promoters describe Halloween Horror Nights as ''intense'' -- though it's all something of a head game, since even the scariest looking ghouls aren't allowed to actually touch the guests. And the shows Bill & Ted's Excellent Halloween Adventure and Rocky Horror Picture Show Tribute are definitely saltier than anything you're going to see at a Disney park.

The event works like this: With a Halloween Horror Nights ticket (advance purchase and Florida residents get the best deals and guaranteed entry, which sometimes sells out), guests get all-inclusive nighttime admission to Universal Studios Orlando. Hours vary, but on weekends, when the event can sell out, you can enter at 6:30 p.m. and stay until 2 a.m.

You'll need the time. Even with special front-of-the-line access (see box), it took nearly five hours to see all the haunted houses and two of the three shows -- and that's without stopping for a snack at Mel's Die-In (cleverly renamed for the evening), slurping down cherry-and-vodka Jell-O shots in plasma bags sold by roving ''nurses'' or taking a spin through the Men-In-Black and Simpson's attractions.

HOUSE PARTIES

The eight haunted houses are the centerpiece, and patrons -- mostly college aged and young adults -- stand in line 45-60 minutes to get through the door. Inside, they're treated to elaborate themed mazes obscured by low light and foggy scenes filled with alien creatures, body collection victims, doomsday survivors, twisted fairy tale characters and the kind of Deliverance rednecks your mother warned you against.

This year's signature is Bloody Mary, the mysterious spook said to be summoned by calling her name into a mirror (and not to be confused with the English queen of history or the cocktail). In Universal's interpretation, Bloody Mary is Dr. Mary Agana, a psychiatrist-to-the-weird who attempts to cure her own fear of death by killing others in the Reflections of Fear haunted house.

It's not giving anything away to say that at Reflections and the other houses you may get sprayed, splattered, breathed on or jumped at -- but unless your ticker is so weak you might literally be scared to death, the pranks are harmless. (Non-monster staffers are stationed along the path to move the flow along and keep an eye out for trouble.) Still, you'll want to put on extra deodorant; these scare tactics will surely raise your temperature.

''It's a lot scarier than I expected,'' said first-time visitor 16-year-old Alexandra Martinez of Weston, visiting with her brother, Antonio, an Orlando student and second-timer. ``I'd definitely come back.''

Veterans dash to Bill & Ted's Excellent Halloween Adventure, an irreverent spoof on politics and pop culture from the year past. This year, both presidential candidates get their fair share of attention, along with Sen. Hilary Clinton, Gov. Sarah Palin, an aging Indiana Jones, Angelina and the twins, Miley Cyrus, Hellboy, Celine Dion, Will Smith and Heath Ledger's Joker.

Tasteful it isn't, but then, at Halloween Horror Nights, gentility definitely isn't on the schedule.