Hork-Bajir-Controllers are Controllers with a Hork-Bajir body. The Yeerks use them because of there physical strength, all the blades on there body, which were used original to cut bark off trees. Late in the story, several book refer to or feature the Blue Band Hork-Bajir. The Animorphs pose as them in book #49 by tearing up Marco's new light blue morphing shirt.