Running Boy also has another nickname in the novel Hoot. His nickname is "Mullet Fingers" because he can snatch mullet fish out of the water with just his bare fingers.
As the novel progresses, we learn that Mullet Fingers/Running Boy is trying to protect the owls which live on the plot of land where Mother Paula's All-American Pancake House is about to be built. He resorts to all sorts of pranks in order to prevent the construction workers from beginning their work. Among other things, we learn that the survey stakes which mark out the construction areas are constantly being uprooted and tossed in different directions. Without these markers in place, construction work cannot begin. We also learn that Roy unwittingly upsets a bag full of poisonous cottonmouth snakes when he is exploring the construction area. Later, we find out that it is Running Boy who is responsible for the snakes being on the construction site.
The foreman of the construction company, Curly, brings in guard dogs as he is less than comfortable with all the strange goings on (baby alligators in the outhouses and flat tires on trucks). However, in the act of releasing the cottonmouth snakes (the ones that Roy accidentally comes upon earlier) inside the chain link fence of the construction site, Running Boy is bitten by one of the dogs. (The dogs do not like the snakes and go into fight mode.) As a result of his bite, Running Boy has to go to the emergency room where Roy protects him by giving him his own name and address so that Running Boy's identity can be kept secret.