Shades are giant bat-like creatures that hunt Group B in The Scorch Trials Official Graphic Novel Prelude. They are Group B's equivalent of Grievers. Group B was previously able to kill one and they hung it up in their meeting room. On a mapping run, one attacks the group and kills Ximena.
Aris later studies it to find the Maze's pattern in written on its wings. Aris also cuts into it and discovers a transmitter that calls the other Shades to it, and brings in WCKD soldiers to save the Icers. The Shades kill the remaining Icers, the equivalent of Gladers in Group !, except for Aris, Sonya, Harriet, and Rachel, who are saved by soldiers. The Shades are not mentioned in the books or movie, and likely did not exist in the novels.