Why Sharkboy?

Where did the name come from? The movie about "Sharkboy and Lavagirl." It just caught on. I was talking to him about how there are different sides to him. "Sharkboy" is when he's intense, either excited or filled with rage. He talks like a monster truck revving its engine. His movements are quick and aggressive, intimidating. "Floppy Boy" is when he's..well, floppy. The fancy word is hypotonia. It's like all of the intertia went out of his body. Movement is limited to dragging himself across the floor. Standing up is impossible. His words become slurred like a stroke victim.

Whatever is going on inside of his brain, no one (except God) knows. Clearly, there is constant changing. I picture a water faucet. It's either dripping or gushing. The moments when he's balanced are the best. That's when he becomes a typical boy.