Buoyant ‘SpongeBob’ brings boatloads of Broadway fun

In Broadway’s delightful but overstuffed “SpongeBob SquarePants,” an oceanfloor volcano about to erupt sends Bikini Bottom residents scurrying — and the musical’s beloved title character into hero mode.

No spoiler on how the natural disaster plays out, but the show directed by Tina Landau explodes with catchy songs, Crayola-bright visuals, goofy humor, not-sosilly messages and lots of heart.

There’s a breakout star turn, to boot. At the center of the musical based on the popular Nickelodeon cartoon is Ethan Slater, a powerhouse performer who brings real emotion to the character. When you’re playing a square yellow sponge who lives in a pineapple with a meowing pet snail on the floor of the Pacific Ocean, that’s something. The Broadway rookie delivers athletic, aerobic, over-the-top joy.

Adding support are Danny Skinner, as SpongeBob’s BFF Patrick, a sea star, and Lilli Cooper as Sandy Cheeks, the squirrel from Texas who knows martial arts and science.

The production smartly shuns prosthetics to match the characters’ looks from the animated series. Instead, undersea denizens are given human form but retain telltale traits. It’s a sound decision that broadens accessibility — for fans and nonfans, adults and kids. “Mummenschanz”-style illusions and synchronized sound effects — SpongeBob squishes when he moves — add to the fun.

Kyle Jarrow’s story is faithful to the cartoon source as it traces new adventures. Like “Hairspray,” the main storyline about the volcano reminds that underdogs and the dispossessed are often the ones who step up.

Subplots are all over the place. Ever-negative Squidward (tap-happy Gavin Lee) craves the spotlight. Sheldon Plankton (Wesley Taylor) hatches an evil plan. Miserly Eugene Krabs (Brian Ray Norris) sees nothing but dollar signs. Momentum stalls occasionally from so many story threads, but David Zinn’s clever sets and costumes offer constant eye candy to compensate.

The same is true of the eclectic, easy-to-like score by an array of singer-songwriters. Jonathan Coulton’s “Bikini Bottom Day” begins things on a bouncy note. The happy, hummable “(Just a) Simple Sponge” by Panic! at the Disco reveals characters. Cyndi Lauper’s rousing “Hero Is My Middle Name” and Lady Antebellum’s punchy “Chop to the Top” make ace motivational anthems. Yolanda Adams’ “Super Sea Star Savior” and John Legend’s “(I Guess I) Miss You” add sweet harmonies. David Bowie and Steven Tyler and Joe Perry also contribute to the seafood-medley style.

Fun is the name of the game in this family-friendly production, but it also offers grown-up insights about community, friendship, intolerance and blindly putting one’s faith in others.

Just a simple Sponge? “SpongeBob,” at the Palace Theatre, is simply a pleasure.