October is when theme parks across the country don their best Halloween costumes and switch from merely entertaining guests to scaring the wits out of them. From a zombie-filled haunted house, to 4D versions of Friday the 13th, here are the all-out transformations that five theme parks are rolling out for Halloween.1. Halloween Horror Nights at Universal Studios Orlando (Orlando, Florida)
2. Knotts Scary Farm (Buena, California)
Having originated the concept of the Halloween theme park season back in 1973, Knott’s Berry Farm is overtaken by 1,000 monsters every October. This year, the park has added yet another terrifying maze to its existing roster of 10, featuring a wicked Snow Queen and an army of dead Vikings. Live shows include the return of "Elvira’s Asylum," a bawdy and fun romp, and "The Hanging," an irreverent pastiche of pop song spoofs with a horror theme.
3. Phantom Fright Nights at Kennywood (Pittsburgh, Pennsylvania)
Kennywood represents a slice of Americana, harkening back to the days when amusement parks had down-home charm, classic fairground-style food, and few high-tech rides. It becomes the biggest horror attraction in Pittsburgh for Halloween, with "scare zones," and a terrifying 4D version of Friday the 13th. Don’t miss out on Ghostwood Estates, a ride that brings you through a haunted mansion. And of course, there's always the Thunderbolt wooden coaster, which gives riders a thrill 365 days a year.
4. Cedar Point's Haunt at Halloweekends (Sandusky, Ohio)
The self-proclaimed "coaster capital of the world" doesn't disappoint during Halloween season. Haunt at Halloweekends features special pop-up attractions like haunted mazes and Halloween-themed shows. Start at the campy Zombie High School maze before exploring the Cornstalkers -- a maze that will have you watching your back. As for the rides, Cedar Point has long been home to some of the best roller coasters in the world, with rides like the new GateKeeper and the all-time-favorite Millennium Force.
5. Fright Fest at Six Flags Great Adventure (Jackson, New Jersey)
Six Flags Great Adventure is the largest theme park in the world, and Fright Fest is their annual festival of all things horror -- scaled to match the epic proportions of the park. Good to know: General admission only covers basic rides, with many of the featured attractions requiring an additional fee. But two that are worthy of the extra fees are the new Big Top Terror haunted house, and the brand-new Blood Shed, where you run through a slaughterhouse chased by mutant half-pigs.
Bonus: For an infinitely gentler theme park Halloween party, there's always Mickey's Not-So-Scary Halloween Party at Walt Disney World.