Mack holds the vital role of being Lightning McQueen's trusted transporter and one of his most enduring companions. Their bond extends back through time, making Mack a cherished and steadfast friend. Together, they operate as integral members of the Rust-eze team within the esteemed Piston Cup Racing Series. Mack's responsibility is to deliver Lightning to every race, solidifying his role as an essential part of Lightning's journey.

Mack's journey into this pivotal role began when he made a noteworthy recommendation. Recognizing Lightning's exceptional talent, he proposed Lightning to Rusty and Dusty Rust-eze during their search for a new spokescar. This recommendation paved the way for Mack to become Lightning's dedicated transporter, marking the beginning of a dynamic partnership that would see them conquering the racetracks and creating unforgettable memories together.