Uncle Al is first introduced brandishing a rifle, chasing off the strange wolf-like creatures that attack the new campers of Camp Nightmoon. While at first he appears to be good-natured, as the story progresses, and the many campers of Camp Nightmoon begin to disappear, he seemingly becomes more suspicious, disavowing any knowledge of the many campers that Billy Harlan notices have vanished over time.
By the end of the story, Uncle Al has Billy and the other campers carry rifles loaded with tranquilizer darts, intended on hunting down Dawn and Dori, two girls who ran off from the girls camp. Billy refuses, eventually pointing the rifle at Uncle Al. But when he fires the rifle, a popping noise is made. It's then revealed that Camp Nightmoon is a government testing lab, and that the rifles weren't actually loaded. Uncle Al, the campers and counselors were all acting to see if Billy would have the skills necessary for his trip with his parents to the planet Earth.
Uncle Al is described as a large man with red-face and large beak of a nose, balding with some blond hair left around his head, beady eyes with bushy blond eyebrows.
At first, Uncle Al is described as the friendly director of Camp Nightmoon, but as the mystery of the missing campers continues to ramp up, he becomes far more suspicious and intimidating, to the point that he tells the campers to hunt down two missing girls from the girls camp. Ultimately, it's all revealed to be an act.
- Uncle Al was used to advertise the Goosebumps television series in a 1995 promotional trailer.
- Uncle Al is accidentally called "Big Al" in the Goosebumps Official Collector's Caps Book.