To Protect and Serve (lost "Cars" animated short; 2015)
"To Protect and Serve" is the unreleased 5th episode of the Tales from Radiator Springs series. It was meant to air in 2015, but as of 2018, it fails to surface.
The short was first announced at D23 Expo 2013 alongside the aired Radiator Springs 500 1/2 short. In March 2014, it was announced that a short was due to release in 2015. This short was found out to be To Protect and Serve in October of the same year.
2015 came and went, and despite diecasts for the new characters (pictured above) as well as several new ones for the pre-existing characters, and even a children’s book version of the short being released, the short never aired. Pixar has yet to explain why the short hasn’t been released yet.
No video of the short has been shown to the public. However, the book does contain images from the short, and the text, for as simple as it is, likely does tell what the story would have been. No more shorts have been announced since To Protect and Serve, and it is likely the series has ended or been cancelled.