Gus setting up a cannon
During a battle on Christophsis, Gus and the rest of their squad were setting up for ambush on the droid army from a tower with Jedi General Obi-Wan Kenobi and Clone Commander Cody. Gus then spotted the battle droids bring up AATs and were splitting up. The battle droids then stormed the tower and Gus was wounded. They were then saved by Jedi General Anakin Skywalker, Clone Captain Rex, and their men before retreating to the rooftop. Before being picked up by Hawk's gunship, Gus then took TJ-55's head back with them.
Gus and the rest of platoon were called to their barracks by Cody and Rex for questioning if someone among them were a spy, much to Sergeant Slick's chagrin. Gus then told them they was being treated for their wound after the ambush and that the medical droid would have the records. They then ganged on up on Chopper when he lied about his whereabouts. However, Slick was revealed to be the true spy and escaped. Gus and the others then went to the base's weapons depot and spotted Slick going into the command center after blowing up the depot.
A clone trooper with the same beard design as Gus appears in "Weapons Factory," but no canonical source has linked the two troopers.