New York's Village Halloween Parade is a quintessentially urban event: about 80,000 fantastically costumed revelers pouring uptown out of Tribeca in an ambulatory yet festive nightmare, their marching band music and manic howls bouncing off buildings as more than a million spectators push in for a glimpse.

But maybe the parade’s weirdest feature is that it begins with a flight of imagination in a Hudson Valley barn. For 21 years and counting, Alex Kahn and Sophia Michahelles of Processional Arts Workshop have chosen the parade's theme and, with the help of volunteers, have built dozens of oversized puppets in a rustic compound upstate in order to bring it to life.

This year's theme is, "Wild Thing!"

The look of the creatures are a mash-up of the Maurice Sendak children's book and pagan rites from Europe. But that doesn't quite do justice to the kinetic performance art that typically emerges from the couple's workshop in the Hudson Valley town of Red Hook. You have to see it.

Jeanne Fleming, the parade’s artistic and producing director for 39 years, has seen it and liked it so much that she keeps hiring them to set the tone and substance of the parade. “Alex and Sophia’s aesthetic is just beautiful,” she said. “They have a way of designing things with a deep artistic sense that are also very accessible to the public.”

Fleming said the puppets, as large and formidable as they are, spark joy with many spectators. But that doesn’t mean they’re predictable.

Kahn recalls one puppet in particular, from the 2000 parade, and how it seemed to exhibit a rascally consciousness. It was a sci-fi sandworm from the Frank Herbert novel, Dune. “It was massive,” he recalled. “Eleven feet in diameter, 75 feet long, and it took 40 people to carry it.”

Kahn and Michahelles abjure mechanized parts in their puppets — the only power propelling them is collective human energy. Here’s Kahn on what happened next:

So this worm took off up Sixth Avenue with smoke belching out of its mouth and the head sort of rearing on this metal frame and you just never knew whether it was going to go down or up 6th Avenue. One person had almost no control over this thing but, collectively, forty people had this kind of concerted motion. And it looked like one organic thing. Which, if you think about it, is what a human being is. We’re a collection of eukaryotic cells all working as a team to create this sense of “I.” We've seen the same thing happen with puppets many times.

Freaky, no?

Still, Kahn and Michahelles say they routinely see their creations take on an animating spirit. They claim that if you make 15-foot-tall puppets with people inside them and set them loose before a madding crowd, what you’ll often see is an independent mind arise from inside them. It’s uncanny and, according to Kahn, salvific.

“I think everybody recognizes that New York needs a night of creative transformation or else the whole city will just, you know, vaporize,” he said.

So how did the crowd react to a giant sandworm going rogue on the streets of Manhattan? Kahn said spectators first play-acted a sense of horror. Then they did what so many do on encountering oversized Halloween puppets: they reached out to touch it. “Especially at Halloween, we embrace things we normally might recoil from,” he said. “It’s this sort of welcoming of, you know, darkness and such.”

Listen to more on this story from Jim O'Grady on WNYC: