Five-year-old Ashlyn Baugher, dressed in her Halloween costume as U.S. Democratic presidential candidate Hillary Clinton, poses for photographs at a campaign "Meet and Greet" in Nashua, New Hampshire October 16, 2015. [Photo/Agencies]

LIMITS TO POKING FUN

The costumes are meant to touch a nerve, but some vendors say there are lines they will not cross.

Ricky's NYC, a beauty supply store that features Halloween costumes, and Yandy.com both decided against carrying a Caitlyn Jenner costume featuring a shiny white padded bustier resembling the outfit the Olympic gold medalist and reality TV star formerly known as Bruce wore to come out as transgender in a Vanity Fair cover story.

"The transgender community is a huge portion of my customer base and is incredibly offended by this," said Richard Parrott, president of Ricky's. "I don't really see anything funny about somebody wanting to change their gender. There is no place to really poke fun."

Jenner told NBC News last month that she did not find the costume offensive: "I'm in on the joke... I think it's great."

Politicians are typically fair game and Ricky's carries a Hillary Clinton mask and Yandy a Donald Trump costume consisting of a white collared shirt, red tie, royal blue blazer and "booty shorts" with extra accessories including a "Making America Great" hat and a straw colored "comb over politician wig."

Halloween costumes that snark rather than spook tend to focus on figures who have fallen from grace, said Jack Santino, who teaches popular culture at Bowling Green State University in Ohio.

"They are people who were kind of ridiculous and there is a kind of 'Emperor Has No Clothes' element," Santino said. "At Halloween, people just mock them to say, 'We all know you're ridiculous. You're not fooling anyone.'"

Irreverent Halloween costumes tend to be worn by adults but some parents, seizing on the natural tendency of babies to look like old men, have been dressing their infants as Democratic presidential candidate Bernie Sanders, with eyeglasses and unruly white wigs, posting their pictures to Twitter as #BabiesForBernie.

Ready-made costumes can be expensive but for frugal Trick or Treaters there is a free online makeup tutorial that a cosmetologist posted on Instagram with tips for looking like Kim Davis, the Kentucky clerk who was jailed for refusing to issue same-same marriage licenses.