What, you expected Sia to stage a traditional concert? Leave it to this anti-pop-star — who shuns fame and notoriety like she shuns displaying her face in public — to sink into the background at her very own concert.

During her gig Wednesday at the Mohegan Sun Arena, the Australian singer-songwriter boasted, as always, an idiosyncratic look. The bangs of her signature blunt-cut, half-white/half-black wig hung down in front of her eyes, obscuring the top two-thirds of her face. (She said, in one of the few words she spoke during the show, that she could see the audience from behind that wall of hair. I remain skeptical.) Perched atop the wig was a giant white bow. She wore a simple white dress that resembled an old-timey hospital gown.

But, despite her quirky outfit and coif, she was really all about not standing out. She retreated from the spotlight — figuratively and literally. She mostly stood on the left side of the stage and sang, as dancers performed onstage and as videos, synchronized to what the dancers were doing, popped up onscreen. Sia was physically impassive, often to the point of immobility.

As aloof as she was physically, Sia was dynamic vocally. She opened the show by hitting big, dramatic notes on the chorus of “Alive” and ended the pre-encore section by traipsing high up the scale in “Chandelier” and “Titanium” with supernatural ease.

Meanwhile, dancers were the ones who provided the physical incarnation of the lyrics’ emotions, moving with abandon and conjuring vivid facial expressions. It seemed like a series of Sonya Tayeh sequences from “So You Think You Can Dance.” Nah, not really Sonya; Ryan Heffington created the choreography here, and what evocative work he devised.

The dancers were led, naturally, by 14-year-old Maddie Ziegler, who starred in TV’s “Dance Moms” and then gained more notoriety as the star of multiple Sia videos. She’s Sia’s little alter ego, and her take-no-prisoners dancing wowed Wednesday. I’d guess that a lot of the teen and tween girls I saw peppering the audience were there to see Ziegler as much as Sia.

The 80-minute show, with no band to be seen, was a series of clever set pieces. When Sia first appeared onstage, she was wearing a big, flouncy white skirt so voluminous, it looked as though it, like Mother Ginger and her Bon Bons in “The Nutcracker,” could house a passel of children. And it did. It turned out that multi-layered “skirt” was really several dancers who burst out as individuals.

As she sang “Diamonds,” the Rihanna hit that Sia co-wrote, sparks of light created the suggestion of diamonds skittering around the stage and then up the back wall, building to a snow-storm-like flurry. A dancer reflected silver beams from reflective gloves and jacket.

During “Soon We’ll Be Found,” Ziegler moved as if she was being impacted by a giant hand shadow puppet projected against the stage backdrop — being poked to the floor or being spun around. It was oddly effective.

And some numbers were, well, just plain odd. For “Titanium,” two performers wore panda and bunny heads and fought each other like cartoon characters in between moments of reconciliation.

This was clearly concert-as-performance-art. It was an intriguing show, even if it was easier to admire than to love. What I’m really curious to know: what will Sia’s next incarnation be?

Meanwhile, the night’s main opening act, the wonderful Miguel, was much more of a traditional performer, connecting with the audience, dancing to his music, and conveying a rock-star aura. He provided a nice counterpoint to Sia’s set.