As millions of American children and adults focused on picking out their costumes or masks for Halloween, a select few have been initiated by experts into the art of deception through disguise.
During a workshop at the International Spy Museum in Washington, 43 fledgling masters of disguise, aged nine to 12, learned the difference between donning a costume and undergoing a complete identity change.
The latter requires skills that parents -- who are banned from the three-hour workshop -- would have preferred their kids didn't acquire.
"To master the art of disguise, you have to learn to sneak around without being detected, to lie and make people believe you," agent Josie, also known as museum staff member Kim Popetz, told the group -- illustrating to some why Washington is the perfect setting for the workshop.
Successful disguise artists not only don wigs and moustaches, but also change their gait, speech and posture, the trainees were told by staff at the museum, whose director Peter Earnest was a CIA operative for 36 years.
The workshop, which cost US$28 per child, is run once a year before Halloween.
"We like to illustrate the difference between disguise and costume, and Halloween is a good time to do that," said Jackie Eyl, youth education manager at the museum.
"Kids associate Halloween with transformation. They are thinking of becoming Dracula, and although that's changing your physical appearance, disguise goes so much deeper," she said.
The tradition of donning a costume at Halloween is said to go back to the ancient Celtic celebration of Samhain, when people dressed up to ward off evil spirits.
Halloween was first celebrated in the US in 1921, and costumes began being mass-marketed for the occasion in the 1930s, according to the US Census Bureau.
Some 36 million American children were expected to "trick or treat" this year. Trick or treating is believed to have evolved from "souling," a tradition among early Christians in Europe who walked from village to village on All Saint's Day -- the day after Halloween -- asking for cakes in exchange for a prayer to expedite the admittance to heaven of deceased relatives
Today, Halloween has become a time for US children to acquire and devour most of the 13kg of sweets the Census Bureau says the average American eats each year.
Many youngsters have also dropped the fear factor from their costume choice and use Halloween as an excuse to live out a fantasy.
"I'll probably be a ballerina for Halloween which has nothing to do with spying," nine-year-old Kyliyah said, apparently unaware of the dancing skills of Mata Hari, who features in the museum's permanent exhibition.
Adults, too, like to dress up and fantasize, and tend to spend more on their outfit than the average US$23 spent by Americans for a Halloween get-up, according to a survey published last month by the National Retail Federation.
"Adults this year are spending US$75 to US$150, and the most popular costumes are pirates, cats, bunnies, devils, fairies -- the usual," said Allan of the Backstage costume shop in Washington.
The most popular adult fantasy costume involved "being a blonde," he said.
When parents returned to the Spy Museum to pick up heavily made-up pre-teen daughters or sons with radical hairstyles and tattoos, they got their own Halloween fright as they came face to face with what their kids' adolescent rebellion might look like.