The Adventures of Shark Boy & Lava Girl in 3-D

Robert Rodriguez is famous for doing it all himself. He’ll write the screenplay, direct the movie, work as his own cinematographer, and even compose the score. The result is that his films often have a unified, distinct vision to them. The downside is that sometimes this unified, distinct vision is boring, and when you’re doing all the work yourself, there’s no one to tell you’re doing it wrong.

“The Adventures of Sharkboy and Lavagirl in 3-D” is based on bedtime stories improvised by Rodriguez and his 7-year-old son, allegedly named “Racer,” though I find that hard to believe. That the film arose from such beginnings is no surprise; it has the random, nonsensical whimsy of a child’s off-the-cuff storytelling. You can see Racer coming up with one idea after another to forestall lights-out:

“And then Sharkboy shows up, and then there’s a fight, and then they have to go to the Dream Lair, and then they have to get the Crystal Heart, and then they have to freeze time, and then there’s an ice castle, and then Lavagirl melts stuff, and then there’s a boy, and then somebody farts.”

If this beginning-less, middle-less and end-less story sounds like it would make a good film, then you and Robert Rodriguez think alike. For the rest of us, it’s a tiresome, generically adventurous tale for kids.

The hero is a fourth-grader named Max (“Cayden” Boyd, speaking of made-up names) who is forever being picked on for living in a fantasy world and having a tenuous grasp on reality. His “what I did on my summer vacation” report is full of visits from Sharkboy (Taylor Lautner) and Lavagirl (Taylor Dooley), much to the dismay of his English teacher (George Lopez), who for some reason continually seeks to stifle Max’s creativity rather than foster it. (The history teacher, I can see. But the English teacher? When the class is focusing on creative writing? That makes no sense.)

Max has two bickering parents (David Arquette and Kristin Davis) who disagree on what to do with him, but no matter. Soon he is whisked away to the planet Drool by SB and LG, his talents (whatever they are) needed to stop the evil Mr. Electric (George Lopez again) from, I don’t know, destroying the universe? SB and LG need Max specifically because he is their creator, having imagined them in the first place. Why he can’t then just imagine that Mr. Electricity dies and never bothers Drool again, I don’t know. I am not familiar with the rules governing one’s delusions.

The movie’s message is that our imagination creates a world that can be as real and as vital as the “real” real world, and that creative thinking among young people should be encouraged. Unfortunately, the movie makes this point 1,000,000,000,000,000 times over the course of its 94 minutes, for an average of 10,638,297,872,340 instances of point-making per minute. Imagination is important. WE GET IT. Now how about coming up with an interesting or clever story? These wan adventures — punctuated by lengthy 3-D sequences in dull, muted colors where nothing “pops” or even needs to be in 3-D — are tedious and uninspired. You’d think a movie about the virtues of using your imagination would be more, you know, imaginative. But this thing — this thing, your own kid could have come up with. It’s fine for bedtime, but who pours $30 million into filming a random bedtime story?

C (1 hr., 34 min.; PG, mild action violence and some crude humor.)