What is the kidnapped boy's appearance?

Johnny, or Red Chief as he calls himself, is described more by his actions that how he looks. The humor in O'Henry's short story, "The Ransom of Red Chief" comes through as O'Henry describes the young boy and his actions. The story should be terrifying: a kid has been stolen from his home. However, Johnny's interactions with his captors prove to be different than expected leaving the reader with a twist characteristic of O'Henry stories.
In the story, Bill and Sam have kidnapped young Johnny Dorset for fifteen hundred dollars. As the only child of Ebenezer Dorset, the kidnappers believe they have a perfect plan to collect quick money. However, Johnny is a little boy with a lot of energy. A sign that the kidnapping won't go as planned happens when they first find Johnny "in the street, throwing rocks at a kitten on the opposite fence". As the men try and lure him away with candy, Johnny hits Bill in the eye with a piece of brick. His nature continues to be described in their first together when he demands Bill plays Indians with him: "Ha! Cursed paleface, do you dare to enter the camp of Red Chief, the terror of the plains?” His game and energy result in bruises for Bill and just a hint of what's to come.
That night Johnny delivers a litany of questions displaying an inquisitive and restless nature. These questions also illustrate to the reader how excited he is to be on this adventure and how he doesn't really see his situation as being kidnapped.

“I like this fine. I never camped out before; but I had a pet ’possum once, and I was nine last birthday. I hate to go to school. Rats ate up sixteen of Jimmy Talbot’s aunt’s speckled hen’s eggs. Are there any real Indians in these woods? I want some more gravy. Does the trees moving make the wind blow? We had five puppies. What makes your nose so red, Hank? My father has lots of money. Are the stars hot? I whipped Ed Walker twice, Saturday. I don’t like girls. You dassent catch toads unless with a string. Do oxen make any noise? Why are oranges round? Have you got beds to sleep on in this cave? Amos Murray has got six toes. A parrot can talk, but a monkey or a fish can’t. How many does it take to make twelve?”

Mr. Dorest knows that his son will eventually tire out his kidnappers, so instead of paying his son's ransom, he offers them a counter offer.

You bring Johnny home and pay me two hundred and fifty dollars in cash, and I agree to take him off your hands. You had better come at night, for the neighbours believe he is lost, and I couldn’t be responsible for what they would do to anybody they saw bringing him back.

At first glance, this might seem cold—what parent wouldn't pay their child's ransom, but Ebenezer is most likely aware of his son's energy (and from his note, it appears the neighbors are as well). This completes our description of young Johnny: an energetic boy, with a wild imagination and a penchant for getting into trouble.