Junior Clown Car
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The Junior Clown Car is a miniature version of Bowser's Koopa Clown Car commonly used by Bowser Jr. Like the original, it is a helicopter-like vehicle with an innocent clown face on the front, which has the ability to change its expression, but with a smaller smile. Its rim and propeller are colored the same shade of green as Bowser Jr.'s head.
New Super Mario Bros. Wii
In New Super Mario Bros. Wii, the Junior Clown Car is introduced as Bowser Jr.'s version of the Koopa Clown Car. Bowser Jr. uses this vehicle twice in battle, and for the third time, he ditches it for the original clown car. Mario, Luigi, Yellow Toad, and Blue Toad can also ride smaller copters exclusively in World 6-Airship. These smaller copters highly resemble a usual Clown Car, except it lacks a face and feature an M or L, or a yellow or blue mushroom logo on it depending on the player. Shaking the Wii Remote produces a move similar to that of a Spin Jump, and crashing into Bowser Jr. with this maneuver is required to shove him into the surrounding electricity.
New Super Mario Bros. U / New Super Luigi U
The Junior Clown Car returns in New Super Mario Bros. U and New Super Luigi U. Like with the Koopalings stylizing their Airships, Bowser Jr. has customized his Junior Clown Car with various enhancements, including boxing gloves. Similar to the Paper Mario version of the Koopa Clown Car and Junior Clown Car, Bowser Jr.'s car has its angry face on for the entire time.
Bowser Jr. and the Junior Clown Car first appear in the first level of Soda Jungle (The Mighty Cannonship in New Super Mario Bros. U, and All Aboard! in New Super Luigi U). Like past encounters, it has a happy face on initially, although it briefly resorts to its angry face when firing Torpedo Teds. After he is defeated the first time, he uses the boxer variation in his second battle in the last level of Meringue Clouds (Boarding the Airship and Bowser Jr. Showdown, respectively), which also contains a payload of Bob-ombs.
In the final level of both games, Bowser Jr. appears in the Junior Clown Car chasing after Mario and attacking by pounding the ground with the car. Bowser Jr. later uses his standard Junior Clown Car to fight Mario alongside Bowser. Unfortunately for him, Mario is able to pounce him and carjack him, as well as use the vessel to ram into his father's head. Bowser Jr. later uses it to escape when Bowser inadvertently destroys what was left of the Airship, with Bowser and the Koopalings holding on (the latter via the former's tail).
Mario Party 9
In Mario Party 9, Bowser Jr. uses his Clown Car primarily as a mode of transformation and uses it (or variations of it) during his minigames. Additionally, in the Bumper Sparks minigame, players use vehicles very similar to the Junior Clown Car's playable counterparts to bump into Bowser Jr. to try to knock him into the electric barrier, just like New Super Mario Bros. Wii. In Bowser Jr. Breakdown, the Junior Clown Car merges with a larger, claw-armed model for the boss fight. Bowser and Bowser Jr. also ride their respective vehicles in the ending.
Mario Party 10
The Junior Clown Car makes an appearance in Mario Party 10, functioning primarily as Bowser Jr.'s mode of transportation. When doing an event that causes players to lose mini-stars (in Mario Party mode) or hearts (in Bowser Party mode), it gains its boxing glove attachments from New Super Mario Bros U.
Mario Party: Star Rush
Paper Mario: Sticker Star
The Junior Clown Car appears in Paper Mario: Sticker Star. It's mostly used as his mode of transportation, but Bowser Jr. uses it during all of his battles. In Bowser Jr.'s Flotilla, it can shoot fireballs or Spiked Balls for attacks. The Clown Car also uses its protection shield from previous titles to block attacks.
Paper Mario: Color Splash
Mario & Luigi: Dream Team
Bowser Jr. and the Junior Clown Car both appear as the final boss of the Battle Ring in Mario & Luigi: Dream Team. While it is not his vehicle's debut, it is officially named the Junior Clown Car for the first time. It guards him from attacks and at one part in the battle becomes its own enemy target separate from Bowser Jr.
When Mario or Luigi tries to use the Jump attack on the Junior Clown Car while Bowser Jr. is outside the Clown Car, they will not attack it, but instead will get in it. They taunt Bowser Jr., and rustle through the Clown Car to find items to throw at him.
Mario & Luigi: Paper Jam
Both the normal version and paper versions of the Junior Clown Car appear in Mario & Luigi: Paper Jam. They are initially used by the Bowser Jrs. to flee Mount Brrr with the Kameks and Princesses. Later, the paper version is used by Paper Bowser Jr. at Bowser's Castle to recapture the Princesses after they escape. Both versions are used during the boss battle against the duo. Much like Dream Team, Bro Attacks that do not hit from above are nullified by the cars.
Puzzle & Dragons: Super Mario Bros. Edition
The Junior Clown Car is used by Bowser Jr. for the entirety of Puzzle & Dragons: Super Mario Bros. Edition. For his special move "Junior Smash", Bowser Jr. rams the party with the Junior Clown Car.
Super Smash Bros. for Nintendo 3DS / Wii U
Bowser Jr. and the Koopalings make their Super Smash Bros. series debut as unlockable newcomers in Super Smash Bros. for Nintendo 3DS and starting newcomers in Super Smash Bros. for Wii U, piloting the Junior Clown Car. Each Koopaling drives a specific-colored Junior Clown Car that have yellow lights for eyes instead of black proper eyes like Bowser Jr.'s version, though since the Koopalings are alternate costumes for Bowser Jr., they all fight identically, using various weapons the clown car is equipped with. In fact, aside from Bowser Jr.'s up special and Final Smash, the Junior Clown Car itself does most of the attacking. In addition, the player takes less damage if the clown car is hit rather than Bowser Jr. or the Koopalings.
Super Mario Maker / Super Mario Maker for Nintendo 3DS
The Junior Clown Car makes an appearance in Super Mario Maker and Super Mario Maker for Nintendo 3DS, replacing the Koopa Clown Car when using the New Super Mario Bros. U style. Aside from its minor atheistic change, it functions exactly like the Koopa Clown Car in other game styles. If the clown car is shaken, it will turn into the Fire Koopa Clown Car.
Mario Tennis: Ultra Smash
In Mario Tennis: Ultra Smash, Bowser Jr. is a playable character who is riding in the Junior Clown Car. The Clown Car actually uses the mechanical arms with boxing gloves from past games to hold the racket.
Mario Sports Superstars
While it does not make a physical appearance in Mario Sports Superstars, gear modeled after the Junior Clown Car (called Bowser Jr. Clown in-game) is obtainable. Additionally, Bowser Jr.'s Baseball and Soccer emblems are patterned after the Junior Clown Car's color scheme.
Mario + Rabbids Kingdom Battle
The Junior Clown Car appear in Mario + Rabbids Kingdom Battle where Bowser Jr. uses it as transportation. Key art of the game also shows it as the cockpit of a mecha piloted by Bowser Jr.. 
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