DOVER — Some visitors to the fifth annual Dover Comic Con event that filled the streets of downtown Dover with superheroes, wizards, pirates and just about every other character imaginable didn’t get it at first on a sweltering Saturday afternoon.

“When I was a kid we got a couple of hours each fall to dress up and walk around the neighborhood and collect candy before experiencing an amazing sugar rush,” said Darrell Thompson, of Dover. “We called it Halloween.

“But after being here for a while, I can see what attracts all of these people to Comic Con. It’s more than just about dressing up. It’s about celebrating people and the things that help make them who they are. It’s fun.”

People from a wide variety of ages put their costumes together and made the trek to the Dover Public Library — and all the other worlds nearby, such as The Green and Legislative Mall — for Saturday’s Comic Con, which was held in around 90-degree heat.

Visitors walked around and took in the wares of 120 or so vendors, who were selling everything from food, to comic books, collectible figures, posters, and everything else in between.

While walking, they would see characters such as Christina Collett, a 28-year-old from Dover, who was cosplaying as Gamora from the Marvel movie “Guardians of the Galaxy,” complete with a little Groot character riding on her shoulder.

It wouldn’t take long for them to ask her if she would mind taking a picture with them. Of course, she readily accepted.

“I’m going on a little over two years cosplaying,” said Ms. Collett, who when not being a superhero is an environmental services worker at Bayhealth. “Last year when I went to this I was Princess Leia. This year I figured I hadn’t done a Marvel character yet … and Gamora is someone people look up to.

“I’m here just for the fun of it. Everyone has a certain fandom that they connect with and it’s just fun when little kids are like, ‘There’s Gamora!,’ or ‘There’s Batman!.’”

There was a kids’ costume contest, along with teen and adult cosplay contests that took place on a stage on The Green, right next to a photo booth, which proved to be very popular.

There were also plenty of other things to keep participants occupied, such as the Mobile Adventure Escape Room Truck, the Pirate Empire Ship and Crew, Mobile Could Video Game Party Truck and a variety of cosplay contests.

However, the biggest attraction also appeared to be the simplest — people watching.

“A lot of different things bring me to Dover Comic Con,” said Evan Meinhold, a 21-year-old from Magnolia who was dressed up as The Riddler from the Batman series. “Anything from meeting new people, showing off what I’ve made, anime props and things like that.

“I just really enjoy the people — and the community is a lot of fun — and sometimes you get to meet old friends that you haven’t seen in a while. It’s just a lot of fun stuff.”

Margie Cyr, the director of the Dover Public Library, said the city started the Comic Con five years ago because similar conventions can be very expensive to attend around the country and this one gives teens in the area a more affordable option and an opportunity to explore the genre of comic books.

Mr. Meinhold said he’s not surprised at all that Dover’s Comic Con has expanded from around 120 people gathered at the library just five years ago to attracting 10,000 or so people on Saturday.

“I expected it to grow every year, especially with what all goes on here, and the more the word goes out, more Internet, and everything else,” he said, “so it doesn’t surprise me that it gets bigger every year.”

Jessica Markland, a 16-year-old from Milford, was cosplaying as Mephisto from the anime Blue Exorcist.

She admitted the heat was bothering her a little bit while she was in costume, but it was well worth it.

“This gives me a chance to hang out with my friends,” Ms. Markland said. “That’s probably the best part — seeing some of my friends I don’t get to see too often.”

Some of the other guests Ms. Markland and others got a chance to meet included: Star Wars 501st Legion: First State Garrison; Delaware Ghostbusters with the Ecto-1 mobile; The Finest: G.I. Joe Costume Club; Delaware Anime Society; Pursuit for Peace Princesses; and the Harry Potter Alliance: First State Potion Masters.

Ray Cunningham was working one of the tents for the Dover Public Library on Saturday, handing out wristbands, distributing bottles of water and providing information to passers-by.

“It’s pretty exciting, there’s a lot of activity,” said Mr. Cunningham. “You could say it’s very different from a normal Saturday in Dover.”

After all, it’s not every day when one gets the chance to see a T-Rex, Thor, Deadpool, Spiderman, Harry Potter, the Ghostbusters, Gamora, Pennywise, and company walking the streets of Dover.

No, Mr. Thompson, it wasn’t Halloween on Saturday in downtown Dover. It was just the latest chapter to the ever-growing story of Dover Comic Con.