In Pixar's Cars 2, what is Mater mistakenly believed to be by British spy Finn McMissile?

In Pixar's Cars 2, Mater is mistakenly believed to be an American spy.

Mater is an ordinary tow truck from Radiator Springs, but Finn McMissile and Holley Shiftwell interpret his strange behavior as evidence of undercover training. Their misunderstanding begins after Mater becomes entangled with the spies during the World Grand Prix. His accidental observations then help expose the plot against the event.

Finn McMissile is a British secret agent, while Holley Shiftwell is an agent assigned to work with him. Mater's role creates the film's central comedy: he has no spy expertise, yet his honesty, luck, and unconventional thinking repeatedly produce useful results.

The mistake is important because Cars 2 divides its story between racing and espionage. Mater is not secretly an agent, and he is not selected for the mission because of a racing title. His supposed identity is an error made by the professionals around him.