By Mariya Manzhos

On Saturday afternoon thousands flocked to Union Square for Somerville’s quirkiest festivity celebrating the invention of marshmallow fluff. From when just a couple of thousand people gathered in the Union Square plaza in 2005, “What the Fluff?” has grown into a massive community celebration of local businesses, talent and creativity.

This year’s Fluff Fest marks the 10th anniversary of Somerville’s beloved tradition, which pays tribute to Archibald Query who in 1917 concocted the marshmallow fluff recipe in the basement of his home in Union Square.

“Fluff Fest is now a regional event,” said Mayor Joseph Curtatone at the festival. “It’s about the creation of Fluff, but it’s also celebrating the creativity and originality of Somerville.”

Expecting over 10,000 people, the organizers made a few changes this year to accommodate the large crowds. The Shenanigans stage, the epicenter of Fluff messiness with games such as Fluff jousting and a Fluff lick-off, was moved into a more visible location. Knucklebones replaced the inflatable bounce house to avoid long lines for children. This year’s newbies, Brooklyn Boulders and Villari’s Martial Arts Center, occupied an additional side stage.

Esther Hanig, the new Executive Director of Union Square Main Streets, headed up the planning of this year’s Fluff Fest, her first. “It’s a very rich event. A lot of moving parts and each moving part has its own detail,” she said rushing to her office above The Independent, her walkie-talkie buzzing with chatter.

With about 45 vendors, there was no shortage of Fluff-inspired deliciousness. Less adventurous eaters could indulge in ubiquitous fluffernutters, Rice Krispies, and marshmallows on a stick covered in caramel and chocolate. Those with more intrepid tastes could visit the Fluff Fear Factor stand to challenge their palette with extreme concoctions of Fluff with tuna, corn, spam and Cheez-its. The Cooking Contest, made up of contributions from the community, included creations such as the pumpkin sriracha fluffernutters with tomato chutney and a chocolate fluffernutter noodle pudding. But the most coveted treats at the Fluff Fest came from Union Square Donuts with their special Fluffanutta’ donut. The line to their stand stayed long for most of the event.

Local pubs also churned out some new Fluff specials. Brass Union put out Fluff-Ferneter with marshmallow vodka, Irish cream and coconut fluff foam and The Independent offered sweet potato fries with candied bacon topped with Fluff, and the fluffin’ tart.

But some vendors and participants were a more natural fit for the Fluff Fest. Autumn Silva has always found marshmallows cute and huggable. Six years ago she decided to give the white sugary puff a personality. At the festival she displayed her collection of polymer clay “marshfellows,” decorative 2-inch figures who are reading, cooking, and sledding. The organizers reached out to Silva last year inviting her to participate. “This year I was right on it,” says Silva.

Ghostbusters, geared up with a toy figure of the Stay Puft Marshmallow Man and bulky proton packs, were some of the only costumed participants at Fluff Fest this year. Members of the unofficial Massachusetts Ghostbusters club, they mostly do charity work in children’s hospitals. But for this Fluff Fest they took ghostbusting a notch up. David Silva, with the help of his three daughters, built a high-tech proton pack imitating the one from the new Ghostbusters movie being filmed in Boston. Vivian, 9, energetically showcased green ectoplasmic residue and psychomagnotheric pink slime. “We’re just a bunch of fans having fun, living the childhood dream of being a ghostbuster,” says Silva.

Delicious aromas of ethnic cuisines wafted from the stand of the Somerville Arts Council’s Nibble program, which empowers immigrants to be culinary entrepreneurs and promotes food and culture as a driving force of economic progress. Louisa from Brazil, donning an intricate white bahiana dress, cooked Brazilian shrimp fritters and plantains. “This festival gives me an opportunity to show my talent,” said Louisa.

With her first Fluff Fest under her belt, Hanig from the Union Square Main Streets is thrilled to be an integral part of the community. “I love this job, because the people in Union Square are so amazing. When we need tents, they lend us tents. Everyone works together.”