In Pixar's Cars, Lightning McQueen's original sponsor is Rust-eze.
Rust-eze is a fictional medicated bumper ointment company whose founders, Rusty and Dusty Rust-eze, sponsor Lightning at the start of the film. Their support gives the rookie racer his entry into the Piston Cup season, although Lightning initially treats the brand and its owners dismissively.
The sponsorship becomes central to Lightning's character arc. After becoming stranded in Radiator Springs, he learns humility and builds relationships with the town's residents. By the end, he chooses to remain with Rust-eze rather than abandon the brand immediately for the much larger Dinoco team.
Viewers sometimes remember Dinoco as Lightning's sponsor because Dinoco is the prestigious team he nearly joins. Dinoco is actually associated with The King in the first film and becomes especially important when Lightning makes his decision after the final race. Rust-eze is the answer for Lightning's starting sponsorship.