Two unlikely protagonists—a brown and a gray lump of clay with googly eyes—squish and sculpt themselves into an array of silly shapes in Claymates, a picture book written by Dev Petty and illustrated by Lauren Eldridge (Little, Brown, June). Morphing into such creatures as an elephant, an alien, a blowfish, a dinosaur, and an octopus, the two good-naturedly flaunt their creativity, and become fast friends in the process.

The story’s friendship theme is fitting, as Petty and Eldridge first connected on Twitter and became close pals through the “kidlit” online community before deciding to collaborate on a book project. “We are a funny pair,” said Petty. “We couldn’t be more different. I am 45 and Jewish and live in Berkeley, California, and Lauren is quite a bit younger than me, grew up in North Dakota, and now lives in Wisconsin. But we immediately hit it off and became very close, even though we’ve never actually met.”

Petty, whose earlier picture books include I Don’t Want to Be a Frog and I Don’t Want to Be Big, had began thinking about the storyline for a book that became Claymates after Eldridge, who is a clay sculptor and a photographer, suggested working together on a project. “I loved the idea of two little characters who start out as balls of clay and can become anything they want to at any time,” she said. “It’s a completely haywire idea, and one with infinite possibilities.”

The author and illustrator collaborated unusually closely as they developed the story and created a fully illustrated dummy, Skyping, texting, and talking constantly (“sometimes 12 times a day!” noted Petty) to swap ideas. “I knew that a standard pitch to a publisher would never do the book justice, and that a fully illustrated dummy was the only way to sell it,” the author recalled. “Creating the dummy was a pretty organic process. We both had a lot of trust in one another and were very open with each other. And we also gave each other a lot of space.”

The fact that she and Petty “have a similar sense of humor” enlivened their brainstorming sessions, explained Eldridge, a debut book illustrator, who developed a love of making small-scale models while studying landscape architecture in college. “I later fell in love with sculpting with clay,” she noted, “and around the same time I also became involved with photography,” two skills that she combines in Claymates. “Photography takes the heavy lifting off the modeling,” she explains. “You don’t have to sculpt the whole figure—only what the lens sees. The object can look weird from other angles. When I sculpted the dinosaur, for example, I didn’t have to make the whole thing. Viewed from the back, it’s all tin foil and wire.”

Little, Brown editor Deirdre Jones was immediately smitten with Claymates when a colleague showed her the dummy, which had been submitted by an agent. “We always share submissions with other editors in our department if we think they might be interested in them,” she noted. “I was immediately hooked on the book, and loved how kid-friendly, deceptively simple, and smart it was. When I presented it to our acquisition team, I said, ‘We have to buy this!’ ”

Jones worked in tandem with Petty and Eldridge to further develop the book’s characters and story arc, and it was a collaboration she thoroughly enjoyed. “Everything about this book was new and wonderful,” she said. “This is the first photographic book I have edited, and this is also the first time that I have collaborated so closely with an author and illustrator together. We had a lot of fun figuring out many of the details—like how to change a peanut into a blowfish into a dinosaur in a series of panels. Dev and Lauren are so easy to work with, and we had a ball together.”

That is a sentiment echoed by the creators of Claymates, who will meet for the first time on June 25, at the book’s launch event at Mrs. Dalloway’s Bookstore in Berkeley. “I am a devout Californian, and I’m very excited to share Berkeley with Lauren,” said Petty. “I feel very lucky to have collaborated with her on this book, and to have found a friendship that is weird, serendipitous, and wonderful all at the same time.”

Claymates by Dev Petty, illus. by Lauren Eldridge. Little, Brown, $16.99 June ISBN 978-0-316-30311-8