Sketch was a clone trooper who served in the Grand Army of the Republic during the Clone Wars. During the Battle of Christophsis, Clone Commander Cody and Clone Captain Rex conducted an investigation regarding the possibility of a Separatist spy among their ranks. They traced an irregular wavelength in external communications to Clone Sergeant Slick and his barracks. Suspecting that one of the sergeant's troopers was the enemy agent, the two clone officers called the squad back to its quarters to interrogate its members. Sketch and "Punch" supported each other's claims that they had been in the mess hall. Slick was eventually revealed to be the spy and escaped before severely damaging the weapons depot. Slick was later apprehended.