Anybody walking the convention floor at GalaxyCon in San Jose will immediately be dispelled of the notion that events like this are only for teenaged boys and middle-aged men nostalgic for their own youth.

Those fans are absolutely there, but they are well balanced out by women, couples and families. getting autographs, attending panels and connecting with each other in front of a booth selling 3D-printed sci-fi props or knockoff Labubus.

You might run into a guy in a Ghostbusters outfit, complete with proton pack, see Starfleet officers from several different eras taking a photo together or a group of young women buying handmade press-on nails from a woman in green face makeup. There are people dressed as recognizable characters from comic books, fantasy movies and TV shows and video games. But some you may not recognize at all, and there’s no better icebreaker at a place like GalaxyCon than asking someone about their cosplay.

That was my experience Friday when I talked to Star Mia O’Fairy and Nico Smith, who were costumed as Stolas, a character from the YouTube show “Helluva Boss.” The two friends — Smith came down from Sacramento for the show — were both excited to meet voice actors from both that show and “Hazbin Hotel,” which is also created by animator and writer Vivienne Medrano, who was very popular with selfie-seeking fans Friday.

Honestly, I didn’t know a thing about either show before Friday, but their passionate fandom was familiar. And it was shared by a lot of other people. “Helluva Boss” star Brandon Rogers probably got the biggest cheers at Friday’s ribbon-cutting ceremony, which included GalaxyCon CEO Mike Broder, original “Hulk” Lou Ferrigno, actor Barry Bostwick from “The Rocky Horror Picture Show,” San Jose Barracuda mascot Frenzy; and San Jose Councilmember Rosemary Kamei, who got into the spirit by wearing a blue uniform top from the animated series “Star Trek: Lower Decks.”

The three-day run at the San Jose McEnery Convention Center culminates Sunday with more star power: Q&As with Ferrigno, actor and director Soleil Moon Frye of “Punky Brewster” fame; character actor Danny Trejo, who has managed to steal scenes in just about everything he’s been in; and cast members from the original “Scream,” including Matthew Lillard and Jamie Kennedy.

That’s just a fraction of the schedule. GalaxyCon is like a carnival that rolls into town with a coterie of tattoo artists, pro wrestlers, gamers, comic book creators, pop culture celebrities, YouTubers and cosplayers. For the whole lineup, go to galaxycon.com/sanjose.