Sox is a robotic support cat in Lightyear, serving as Buzz Lightyear’s loyal companion and assistant. Designed to provide practical help, analysis, and emotional support, he often acts as the calm, witty counterbalance to Buzz’s intense determination. Throughout the story, Sox helps with strategy, technical problem-solving, and mission support, becoming an important ally during the effort to complete Buzz’s mission. Despite being a robot, he is one of the most endearing and memorable characters in the film.