Revealing mistake: When Lavagirl burns the diary, it goes up in flames. However, if you watch Max and Sharkboy, they look at an unseen object falling to the ground. The unseen object is the diary, taken out in editing. Later, Max looks back at the diary on the ground.
Revealing mistake: Near the end, Max's father is holding onto a tree to avoid being blown away by the tornado. However, the next time you see him he starts to talk to Max with both of his hands off the tree and he isn't being affected by the incredibly strong wind at all.
Revealing mistake: When Sharkboy is running at a fast speed to get Lavagirl to the volcano, in one shot as he runs with her cradled in his arms, it is clearly not her, but a dummy. (01:07:25)
Revealing mistake: When Sharkboy and Lavagirl are riding on Tobor's eyes to the Train of Thought, the eyeballs they ride on continue to blink shut which means they are moving forwards and back. However this doesn't affect either one of their's stance, and they just stand completely still. (00:36:30)
Revealing mistake: In the Milk River scene, you can see the cherry on the sound stage they are recording on.
Answer: According to Taylor Lautner, the actor who played Sharkboy, he approached the role as if Sharkboy was jealous of Max because Sharkboy has a crush on Lavagirl and she pays Max lots of attention.
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