The Yellow Spotted Lizard is a venomous creature that inhabits the arid wasteland of Green Lake. Each lizard has yellow eyes, black teeth, red-rimmed eyelids, a milky white tongue, greenish skin, and exactly 11 spots; however, it is a common legend that you get close enough to count the spots, you will die. A Yellow Spotted Lizard is incredibly venemous, enough that one bite injects enough venom to cause a slow painful death, with no known antivenom and a 100% fatality rate. Interestingly, onions are a strong repellant for these lizards. Stanley Yelnats IV and Zero (Hector Zeroni) were both saved by that fact after eating a large amount of onions, the same method Sam used, resulting in them smelling of onions. This prevented the lizards from biting them, despite being swarmed by them.
The actual lizards used in the film were actually Bearded Dragons, which are harmless and nonvenomous. Nine Bearded Dragon lizards were on call for the parts of the lizards in the film. A non-toxic children's finger paint was used on the lizards to make them appear bright in color and computers helped create some of the lizard action and production created fake life-like lizards for some of the other scenes.