Rainbow Kitten Surprise, or RKS to fans, took to the stage and an eager crowd at Oakland’s Fox Theater on June 4. With drummer Jess Haney sat on a raised platform near the rear and the rest of RKS positioned a decent way apart, the stage appeared larger than usual. The visual smallness of the members seemed at odds with the massive body of sound that comes out of the group. Initially, the open space threatened to swallow the band whole, but after it opened the show with playful and folky “Matchbox,” it became clear that the group would more than make use of the space.

Over the course of the 22-song set, the audience came to know well all that the band could do with the space. And as the band tore into “It’s Called: Freefall,” it became clear how invested fans were in the music, the band, the night and everything in between.

The crowd filled the space till it seemed it might burst. Frontman Sam Melo was all swaying hips and graceful hands — he had an energy that was irreplicable, uniquely his. But then, so did the entire group. At various intervals, any member (save Haney) was liable to christen the stage with whimsical twirling or other demonstrations of their intimate connection to the beautiful music they were making. There was joy in every movement, and it permeated the crowd. Every audience member became a ready recipient for the message of the night: Enjoy yourself.

And in this way, a feeling of spontaneity arose. Though every spin was in time with the music, there was never a feeling of over-rehearsal. Every miraculous vocal acrobatic or guitar solo felt as if it were simply this easy and effortless every time.

This energy translated to all of the songs RKS performed, be they the somber, the sinister or the jaunty and joyous numbers. The band’s sound — folk-kissed by both the grit of Johnny Cash and the carefree energy of Sublime in its heyday — was chameleonic and energizing. When the band performed songs like “Hide” and “All That and More (Sailboat),” the room was abuzz with what felt like a communal love and sense of understanding. In the case of the latter, as the band sang the words, “My baby’s a sailboat captain at sea,” the audience sang back with such conviction that you’d think everyone in that room was the forlorn spouse of a wandering mariner.

And rather than having a set list that compartmentalized all of the various sounds that characterize the group’s music, the band worked through what felt like an incongruous progression of its discography — some songs were more gentle and acoustic, while some were darker. This near unpredictability in song order kept the show refreshing and exciting.

If there was to be any tell of what kind of song was to follow any number, it would come from the show of lights, which acted more as a presence than as a supplementary effect. The lights would go from warm, honeyed tones to deep and dense reds or blues to signal a tonal shift; they themselves could have been a sixth member of the band.

There is an undeniable talent evident among the band members — and at the Fox, it showed. Melo’s ease of movement, from verbose yell-singing to gentle crooning to rapid-fire sing-talking, was nearly unbelievable. During the funky “When It Lands”, Melo shot through the spitfire middle with seamless expertise; he never tripped up, even when he did trip physically. And even that was turned into a swift roll across the stage, making it just as much a spontaneous choice as an unplanned blunder.

The way the band members interacted with each other brought life to songs that felt as if they couldn’t be any livelier. As the band concluded the show with an explosive performance of “Run,” it was clear that by the end of the night, all that space had been filled to the brim with talent, reverie and the simple fact that RKS is a force to be reckoned with.