When Billy Harlan arrives at Camp Nightmoon, he is told by the camp director, Uncle Al, to stay away from the Forbidden Bunk. Billy follows this rule, but his fellow bunk mates are a lot more curious to find out exactly what's inside. Their counselor, Larry, warns them that if they break Uncle Al's rule they will be eaten by Sabre, who allegedly devours one camper each night. When strange things start to happen and campers start to go missing, Sabre is believed to be responsible. Despite this, Billy never actually encounters Sabre.
The end of the book reveals Billy's entire ordeal to be a test to see if he was prepared for life on another planet. Because of this, it is left unclear if Sabre ever existed at all.
In the TV series, Sabre is featured much more prominently. The creature nearly attacks Billy when he arrives at Camp Nightmoon. The ending of the episode reveals Sabre to be an animatronic controlled by George, one of the camp's employees.
Very little description is given to Sabre beyond it having red eyes. The episode gives Sabre a more distinct look.
- The animatronic Sabre was later recycled for Ripper the Killer Beast in the TV adaption of One Day at HorrorLand.
- Originally, Sabre was in the second draft of the Goosebumps movie. However, he was among the monsters that were scrapped.