Tomber was serving a twenty-year to life sentence in a a Moroccan impound lot where he was saved by British secret agent, Finn McMissile. The two developed a close friendship where Tomber became Finn's secret informant when he started working as an auto-parts dealers in Paris, France.
Tomber is a dubious little French car with an unusual, and very unstable, three-wheeled design that befits the meaning of his name – to fall. By trade, he deals car parts from a stall in a Parisian market—though his questionable merchandise sources have led to his reluctant acquaintance with British secret agent Finn McMissile.
At first, Tomber appears to be a shady con man who is trying to bribe his customers into paying him with their money. However, upon his interactions with Finn McMissile, Tomber is actually a kind and helpful individual who is willing to give spies information to help them with their missions. Tomber's willingness to help spies comes from being grateful to Finn McMissile for saving his life from serving in an impound lot. Tomber also can become good friends with anyone who shares knowledge in auto parts, as shown with Mater where they were both impressed with each other's knowledge in automobile parts.
Tomber largely resembles the English Reliant Regal three-wheeler, but also bears similarities to a French Citroën AMI, most notably in his double-headlight structure. The Citroën DS also seems to have been an inspiration, mainly for the position of his rear turning indicators, which are situated in the upper corners of his rear window.
John Lasseter said about Tomber's design : "we made up our own three-wheeler. I love French auto design of the early ’50s, ’60s, early ’70s of Citroëns, Renaults, and Peugeots. They’re so unique. So we kind of pulled from a lot of our favorite older French cars and kind of merged it together into this car."
Tomber's license plate is PCS NO1R, an abbreviation for the French "pièces noires," a reference to the black market parts which he deals.
Tomber is seen at the Marché Aux Pièces located in Paris, talking to someone when he notices Mater suddenly backing away and hiding. Upon closer inspection, Tomber notices Finn McMissile's reflection through a mirror, causing Tomber to flee. Tomber is pursued throughout the black market and makes several attempts to lose his pursuers, only for them to keep their trail on him. When Holley Shiftwell suddenly appears in front of him, Tomber tries to turn around, only to lose friction and crash, due to only having three wheels. Holley then tasers Tomber, only to stopped by Finn who angrily reprimands her and orders Mater to tow Tomber.
Tomber is taken to an abandoned warehouse where he angrily confronts Finn for Holley tasering at him, only to be told that Holley was new to field agency and did not know that Tomber was Finn's informant, something that surprises Holley. Tomber rebuffs Holley for being a rookie field agent and happily shares some memories with Finn when he recounts the time of saving Tomber from the Moroccan impound. Holley then shows a picture of a Rover V8 engine that she and Finn received from Mater (who had unknowingly received from Rod Redline before he was captured and killed) where Tomber is disgusted at the sight of the engine, saying it is the worst motor ever made. However, Tomber notices several boxes of rare parts in the photograph next to the engine, revealing to the agents that he sold the parts to a car, but does not the car's identity as he always did business with Tomber on the phone. Tomber confesses he always wondered why the car needed so many parts, but says he now knows why because the car needs parts for his engine, which is the Rover V8 engine shown in the agents' photograph.
This makes Mater reveal that the owner of the engine is an engine is a lemon and explains the nature of lemons. He then identifies Gremlins, Pacers, Hugos, and Trunkovs as lemons, which makes Holley realize that everyone in the plot is a lemon car. Finn takes it from there and deduces that the lemon families are taking orders from the car behind the engine. At the sound of this, Tomber reveals that the lemons are hosting a secret meeting in Porto Corsa, Italy, which is also where the second race will take place, and the lemon boss will most likely be there as well. Tomber tells them that their chances to find the lemon boss are more than good as he had just sent the lemons' leader new parts to Porto Corsa. As Holley and Finn make preparations to get to Porto Corsa, Tomber and Mater cordially acknowledge each other, as Tomber was clearly impressed with the tow truck's knowledge in auto parts just as Mater was impressed with Tomber as well.
Tomber is an unlockable playable character in Cars 2: The Video Game, unlocked once access to Clearance Level 6 has been granted. He is a light weight vehicle, with lots of speed and little power.
- A promotional artwork for this film (see below) actually incorrectly portrayed Tomber as a Lemon and therefore, Finn McMissile's enemy. In the actual movie, he is McMissile's ally.
- Three-wheeled cars were first meant to be part of the Lemons group.
- His name is French for "Fall."