Lulu, played by Casie Platt, explains to Mr. B, inhabited by Vaughn Irving, why he should be her pet in “Lulu and the Brontosaurus” at Imagination Stage. (Margot Schulman)

Watching a spoiled child kick up a tantrum doesn’t sound like much fun, but it is — lots — when it happens at Imagination Stage. Plus, she meets a dinosaur.

District-based writer Judith Viorst and composer Shelly Markham have adapted Viorst’s 2010 picture book (with illustrator Lane Smith), “Lulu and the Brontosaurus,” into a musical. It’s having a world premiere at the downtown Bethesda company for young audiences.

This tale of a brat who learns to be nice without losing her edge takes the audience on a ride scattered richly with broad yuks, subtle satire, whimsicality and poignancy.

Lulu (Casie Platt), an only child, bedevils her parents (Tracey Stephens and Doug Wilder) with screaming, kicking, fall-on-the-floor hissy fits if they even hesitate before giving her what she wants. As the Narrator (Lauren Du Pree) observes, “Lulu is a pain in the butt.”

In her family’s French Provincial living room (Milagros Ponce de Leon designed the pleasing, picture-book-style sets) Lulu announces that for her 10th birthday, she wants a brontosaurus. Her parents tell her that a brontosaurus is far too large to be a pet. They hold firm, so Lulu stomps off to snare the beast herself. She sings, “I’m gonna, I’m gonna, I’m gonna gonna get / A bronto, bronto, bronto, bronto-saurus for a pet.” Exhausted and not inclined to follow, her parents have a snack and doze off.

Thus, it comes to pass that Lulu learns about kindness and friendship from a gigantic, no-longer-extinct-for-the-purposes-of-this-story herbivore (Vaughn Irving). But first, on her way through the forest, she does a tango (droll choreography by Ilona Kessell) with a slithering Snake (also Irving), lays some flattery on a vain Tigress (Stephens) in pantaloons, and refuses to cringe before a blustery bear (Wilder). Debra Kim Sivigny has created an ingenious array of costumes for human and beast.

Some lovely puppetry makes Lulu’s encounter with the brontosaurus a stunning event. We see only the creature’s green plush neck and head (designed by Matthew Pauli, operated and voiced by Irving), but it looms over the full height of the stage. And when the brontosaurus tells Lulu how lonely he is up in the leafy canopy, the sense of his apartness brings on a real twinge.

So it’s understandable that the brontosaurus wants Lulu to stay in the forest and be his pet. He tries to keep her, but Lulu plots her escape, trying not to hurt his feelings — a new thing for her.

Platt tears up the stage and gets big laughs from tantrum to tango to her first choked utterance of the word “please.” That she wanders off-key belting some of Lulu’s songs could be forgiven as a character note, given the kid’s personality. As Lulu’s Mother and the glamorous tigress, Stephens shines as a funny and highly skilled singer/actress. Irving’s brontosaurus voice veers too close to Kermit the Frog’s, yet he brings great feeling to the role.

The show has a prolonged coda as Lulu makes her way back to her parents. The young audience got a case of the fidgets one day during those last few minutes. But the first 85 make it well worth the trip.

Horwitz is a freelance writer.

Lulu and the brontosaurus

Book and lyrics by Judith Viorst, music by Shelly Markham. Directed by Janet Stanford. Music director, George Fulginiti-Shakar. About 90 minutes, including intermission. Through Oct. 27 at Imagination Stage, 4908 Auburn Ave., Bethesda. Recommended for ages 4 to 9. Visit www.imaginationstage.org or call 301-280-1660.