We're three weeks out until Halloween, and the big shopping rush doesn't usually come until a few days before, but party and costume shops across New Jersey already have a sense of the must-have looks for Halloween 2016.

Some stores knew it before the season began: costumes related to the supervillain film "Suicide Squad" would be the biggest hit.

Characters such as Harley Quinn and the Joker are in high demand at Spirit Halloween in Old Bridge, where workers are struggling to keep up.

"As soon as we put it out on the shelves, it's outta here," said manager Doris Aber. "We can't keep it in stock."

According to Steven Eisenman, owner of New Jersey-based Party Fair, retailers everywhere are in short supply of what customers want the most this year, mainly because costume makers weren't expecting the Suicide Squad hysteria.

"I don't think they took a big chance on it when the movie came out," Eisenman said. "The manufacturer went back to the drawing board when they saw the movie was a hit."

And it's mostly adults gobbling up the Squad goodies, stores say.

For kids, stores are seeing the most action in the superhero category - particularly Avengers, Batman and Teenage Mutant Ninja Turtles.

In Bergen County, many older shoppers are apparently using Halloween as a platform to support, or embarrass, a U.S. presidential candidate.

Donald Trump and Hillary Clinton masks (Tomohiro Ohsumi/Getty Images)

"The hottest items are the Hillary Clinton and Donald Trump masks and wigs - can’t keep them on the shelves," said David Weil, owner of The Party Box in Lodi.

Based on the number of masks sold, Weil says his shop has correctly predicted the winner of the presidential election over the past few decades. So far this year, the shop has sold more Clinton masks.

"We're also seeing a lot of couples costumes - bacon and eggs, flip flops, ham and cheese, peanut butter and jelly," Weil added.

Other fast-moving costume ideas reported by New Jersey stores include "Star Wars," Pokemon, Super Mario and Luigio costumes and the inflatable T-Rex costume.

On the opposite end of the success spectrum, clown-related merchandise has not been moving well, as New Jersey cops and schools advise against or ban clown attire due to a recent string of "creepy clown" sightings, threats and hoaxes.

Logan K, manager at Halloween City in Howell, said she has not sold one clown outfit, which he says is odd through the first week of October.

"People will come in and put the masks on as a joke, but no one actually buys them," she said.

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Contact reporter Dino Flammia at dino.flammia@townsquaremedia.com.