Mater the Greater is the Cars: Mater's Tall Tales short in which Mater claims to be a famous stunt performer.
The short centers on Mater telling Lightning McQueen about his supposed career as a stunt performer. His story includes elaborate jumps and dangerous feats, presented in the exaggerated style that defines the Mater's Tall Tales series. As with many of Mater's tales, the audience is invited to enjoy his storytelling rather than treat every claim as established history.
Cars: Mater's Tall Tales is a series of short animated films focused on Mater and Lightning McQueen. The shorts were released through Disney platforms and home-video releases before and around the period of the feature films.
Tokyo Mater is about a street race in Japan, Rescue Squad Mater concerns emergency work, and Monster Truck Mater centers on a monster-truck setting. Those titles are related shorts, but they do not specifically identify Mater's claimed stunt-performer story.