“With other krewes, people pay thousands of dollars to pay artists that make their floats for them,” said Ryan Ballard, one of the Chewbacchus founders. “We want to make a place for people to do it themselves.”

Mr. Ballard and his co-founders, Brett Powers and Kira Haubrich, envisioned Chewbacchus as a New Orleans take on “Star Wars” and science fiction fandom. They did not expect a response much beyond their circle of friends, but as word spread through the city, more and more people started to show up to build floats and assemble costumes with them. By the time their inaugural parade rolled the Sunday before Mardi Gras last year, they found themselves with 400 members. They had touched a nerve.

After the group’s initial success, it became clear that Chewbacchus was a force with staying power. Now the leadership is working to cement their krewe’s place in the annual ritual. The founders have taken leadership roles as “overlords,” and the krewe has expanded with a host of subgroups with names like the Death Star Steppers, the Chewbikkan Cyclopods, the Sci Fi Brass Band and the Wild Tchewbacchatoulas, a nod to traditional Mardi Gras Indian culture.

Amateur float builders like Tim Momenee, a Lockheed Martin engineer, are answering the Chewbacchus call for outlandish creations. For the past few weeks, he has been working with chicken wire, insulation, mattress pads and faux fur to turn an old pink go-kart frame into a bantha, the wooly mammoth-like creatures from “Star Wars.” He powers it with half a bicycle hooked to the wheels.

Mr. Powers, who goes by the name Ghetto Fett during Mardi Gras, says Chewbacchus and krewes like it are a response to the exclusivity of the older groups. Chewbacchus does not have any waiting lists or recommendation requirements, and dues are only $42 (an arcane numerical reference to the novel “The Hitchhiker’s Guide to the Galaxy”).