In the book The Scorch Trials, each Glader was secretly tattooed on the back of their necks with information clearly identifying them as WICKED test subjects. The tattoos were a variable to see how each individual reacted to the role they were given. Each tattoo began with "PROPERTY OF WICKED" and included each subject's group (A or B), their subject number, and in some cases their title. The title was given by WICKED based on their character and personality, and illustrated the role WICKED intended for them to play. For example, Newt's title was "The Glue", meaning that Newt's personality as the level-headed center of Group A was the glue that kept the group together; it also referenced the fact that he was the control subject of Group A. As for Thomas's title, "To be killed by Group B", it was intended to foreshadow WICKED's designs.