SINKING SPRING, Pa. -- Do you have gymnophobia -- the fear of being nude?

One Halloween attraction is making history as the first to put that phobia to the test by challenging its guests to go through a haunted house completely naked.

For $20, guests can bare it all and go face-to-face with their worst nightmares inside "The Unknown" -- a haunted house at Shocktoberfest in eastern Pennsylvania.

Shocktoberfest, a haunted "scream" park featuring numerous scary attractions, says the idea for their new "Naked and Scared" challenge was motivated by Discovery Channel's "Naked and Afraid" reality show.

"Naked and Scared" is only available after midnight once the park's regular hours of operation are closed.

Guests can choose to experience the attraction "nude" or "prude" -- either fully undressed or wearing only underwear.

All participants must be at least 18 years old and sign a waiver.

Shocktoberfest officials say guests undress in a "semi-private preshow building" before entering the haunted attraction. Those who face the naked challenge will never be in view of minors or non-participating customers.

A disclaimer on the haunted park's site indicates the following: Shocktoberfest has created this experience so their customers can explore a new level of fear. This is about fear and pushing oneself out of their comfort zone. This is not about sex. No sexual misconduct, inappropriate or disrespectful behavior will be tolerated.