This past summer belonged to Charli xcx . The British singer’s album brat , released in early June, sent out a bat signal (or, perhaps, a brat signal), encouraging fans to be their most feral selves—to be 365 party girls, to be messy and unapologetic. As summer faded into fall, many wondered what would come next.

But as a sea of chartreuse began to close in on Madison Square Garden hours before Charli and Troye Sivan were set to take the stage on their Sweat Tour, it became clear that the craze isn’t going anywhere. What makes an outfit brat exactly? Charli’s stylist Chris Horan weighs in: “Anything bitchy and never anything too perfect,” he tells Vogue . While there was no shortage of “brat green,” others got into the spirit with quippy slogan tees, lingerie, chunky silver jewelry, chainmail, chaps, furry boots, and bloomers galore.

Concertgoers took that directive to heart. Some people leaned into the DIY spirit, like Kelley Heyer, who created the viral “Apple” dance, which she performed live during the song. “This is a skirt that I thrifted, and I bedazzled it with a brat tramp stamp on the back,” she says of her black pleated micro-mini.

But some attendees went full-throttle on the fashion in Diesel, Acne Studios, Balenciaga, Heaven by Marc Jacobs, and Rick Owens. Lawson Taylor accessorized custom Eleen Halvorsen chaps and a corset with a neon green Balenciaga Le City bag and Rick Owens boots. Meanwhile, Bridget Shurdod purchased her entire outfit .