In Pixar's Cars (2006), Rust-eze is the sponsor whose logo is painted on Lightning McQueen's race car. Rust-eze is a fictional bumper-ointment brand that sponsors McQueen when he begins the film as a rookie racer.
McQueen initially considers Rust-eze an unimpressive sponsor and dreams of replacing it with Dinoco, the prestigious company associated with The King. After McQueen chooses to help The King at the Dinoco 400, he is offered a chance to join Dinoco but decides to remain with Rust-eze.
The sponsorship is therefore more than a visual detail. It marks McQueen's movement from ambition based on status toward loyalty and gratitude. Rust-eze also remains important in later films, even as McQueen's racing identity and team change.