"Can you dig it?"
"Some secrets are too big to keep hidden."
A boy is wrongly convicted of a crime and sent to Camp Green Lake, a work camp for juvenile delinquents. The camp is on a dry lake bed in the middle of the desert, where it hasn't rained for a hundred years. The warden makes the boys dig holes every day but nobody knows why.
The boss carries a pistol that he says is only for Yellow-Spotted Lizards. He tells the boys that if one of the lizards bites them, it always causes a slow and painful death. (Like most dangerous animals in movies, the lizards bite for no reason at all.) The camp has signs all over warning the boys about the lizards. One night we see him shoot the head off one of the lizards.
For some reason, the lizards hang out in groups at the bottom of the holes the boys dig, but the holes are too deep for them to escape. When a couple of boys fall into a hole full of lizards, they have to remain still so they will not die from lizard bites.
The lizards we see are actually Australian lizards called Beardon Dragons that have been painted. Needless to say, Bearded Dragons are harmless, and they're also very popular pets. When the lizards attack, we see computer-generated lizards with fangs and frills similar to another Australian lizard, the Frilled Lizard.
It's easy to complain about the egregious inaccuracies regarding these lizards, but it's best to see this entire film as nothing more than a family-friendly Disney fantasy. The author of the book on which the movie is based was also the movie's screenwriter, but I don't know if the lizards in the movie are similar to the lizards that appear in the book, if indeed there are any lizards in the book.