Let's Eat Grandma's Rosa Walton and Jenny Hollingworth love duality.

They look like they could be twins (actually, they've been friends since age four), and their band name comes from the grammar meme that reminds readers of the comma's importance with results that are either sweet ("let's eat, grandma") or horrifying ("let's eat grandma").

The duo has it both ways on the often fascinating I, Gemini, which they recorded while they were still in their teens.

Hollingworth and Walton sprinkle their music with whimsical instrumentation, whether it's the accordions, glockenspiels, and recorders that appear on nearly every track, or the intentionally ridiculous sax solo on "Sax in the City." Meanwhile, their vocals circle each other like an adorable coven that's all the more dangerous because of its seeming cuteness; the shrieks that end "Sleep Song" would be right at home in a horror film or at a slumber party.

It's easy to hear similarities to CocoRosie, Kate Bush, and Björk in Let's Eat Grandma's music, but Walton and Hollingworth are more spontaneous than any of those artists.

There's a youthful audaciousness to the way they jump from sound to sound and place to place throughout I, Gemini: the mysterious album-opening "Deep Six Textbook" transports listeners from classroom tedium to a seaside reverie via dreamy synths, a somber trip-hop beat, and slightly eerie pat-a-cake handclaps (later, "Uke 6 Textbook" reworks the track as more conventional indie folk that's nearly as winning).

Elsewhere, the fusion of '90s Europop and rap on "Eat Shiitake Mushrooms" feels like music for an imaginary dance club, while "Chimpanzees in Canopies"' strings and dulcimer lend an ancient cast to the song.

As enjoyable as I, Gemini's unpredictable combinations of sounds are in their own right, they're most potent when illustrating the clash between the ways girls are expected to act and how they actually are.

Let's Eat Grandma shatters "Rapunzel"'s cloistered mood as they wail "I'm not having fun in this fairy tale," taking the story back from Grimm in the process.

At times, Hollingworth and Walton's freewheeling experimentation gets a little too chaotic, but I, Gemini is an adventurous debut filled with moments of surprising beauty and humor.