Cars 2 was the first Pixar Cars film to feature Mater as a secret agent.
In the 2011 sequel, Mater is mistaken for an American spy after meeting Finn McMissile during the World Grand Prix. His accidental involvement pulls him into an international investigation involving criminals, secret technology, and the alternative fuel Allinol.
The spy story gives Mater a much larger role than he has in the first Cars. Lightning McQueen remains central to the racing plot, but Mater’s misunderstandings and unexpected instincts drive much of the espionage narrative.
Cars 3 shifts away from the international spy structure and returns to McQueen’s racing career and his relationship with Cruz Ramirez. Cars on the Road, released later as a Disney+ series, also follows McQueen and Mater, but it was not a feature film in the original trilogy.