Otherworldly banshees or a pair of hipsters reprogramming Enya with Florence And The Machine.

On first sight and sound, the Casady sisters could be either. But read the back-story (itinerant childhood, Steiner school, Shamanic father) and you’d struggle to disagree that Bianca “Coco” and Sierra “Rosie” are as unearthly as is possible without actually being from Mars.

One sings like an opera queen and plays the harp; the other shouts, sings and raps in a childlike croak (think Joanna Newsom). Separately their voices would be interesting; together the juxtaposition makes for that rare quality: individuality.

In Brighton to support fifth record Tales Of A Grasswidow, the beatboxing was back in a big way (the vocal chords and breathing tricks of Tez provided all the percussion), which made the new material the evening’s most cohesive.

The set was as baffling and intriguing as the avant-garde duo’s earlier records. A washing line hung over the stage with clothes for dressing up – Sierra did burlesque, Snow White and Dorothy; Bianca even became the scarecrow, putting the girls into the American rural idyll they never had as youngsters.

As the light dropped, a mirror at the back stopped looking human-like with its top hat, arms and legs (a missing other, perhaps?) and Sierra sang the tragedy Burn Face while staring into the looking-glass like a princess, back to the audience, face projected on to a big screen.

Before scuttling off at the end, Bianca plonked elatedly on a grand piano like a joyous child because for these two, life and art are theatre. And no matter what we experience, we should never grow up.