Sometimes Robert Rodriguez has a novel idea that becomes a movie coup. “Spy Kids,” for instance, or the amazing-looking “Sin City.”

And sometimes, he delivers a stinker.

“The Adventures of Shark Boy and Lava Girl,” which he credited to a story idea by his son, Racer, is that rare film that can cause actual physical pain while watching it. It is a headache-inducing misuse of 3-D, a gimmick Rodriguez likes a little too much.

A kid named Max (Cayden Boyd) dreams up an imaginary world (Planet Drool) protected by superheroes Shark Boy (Taylor Lautner) and Lava Girl (Taylor Dooley). Shark Boy is a real King of the Sea, with fins, gills and teeth you wouldn’t want to mess with. Lava Girl can start fires and melt through pretty much anything at will.

But the dream planet is in danger. Mr. Electric and his team of Plughounds (electrical cord-beasties) want to cast the planet into darkness.

'The Adventures of Shark Boy and Lava Girl' uses 3-D glasses to tell a tale of the imaginary world Planet

S-boy and L-girl show up and fetch Max, thus giving the lie to the hateful bully in his school who insists that they don’t exist. Max, Boy and Girl must travel through the Passage of Time, down the Stream of Consciousness, over the Sea of Confusion, take the Train of Thought, all to get to the Dream Lair where Max, the dreamer, can set everything right.

Very “Spy Kids 3-D” in plot, characters and villains, if not in execution. Rodriguez cast David Arquette and Kristin Davis as Max’s parents, and gave them nothing to do. Even their Planet Drool doubles have nothing to do.

The movie is unbelievably ugly. The garish colors Rodriguez loves so much wash out in 3-D. The kids aren’t very good actors, and gadgets and cool sets are not enough to hold our interest in between instructions to put our 3-D glasses on or take our 3-D glasses off.

Maybe the 3-D won’t give you a headache. But “Shark Boy and Lava Girl” certainly isn’t worth the risk.