Bowser Jr.

Bowser Jr. (, Koopa Junior) is the son of Bowser and a major villain in the series.

Origin
Bowser Jr. is the mischievous son of Bowser and the prince of the Koopas. He bears a striking resemblance to his father when he was a child, having beady eyes, a rounded snout with fewer contours, and hair tied in a small ponytail.

He debuted in , where he painted over most of with a  he somehow obtained from. The "paint" was often referred to as "goop". Bowser Jr.'s graffiti caused the s scattered about, causing its sunlight to recede. Bowser Jr. did these things disguised as Mario, tricking the denizens of Isle Delfino into thinking he was the culprit. In disguise, Bowser Jr. appears similar to Mario, but has a higher-pitched voice and a gelatinous, dark blue body with glowing red eyes. The disguise, referred to as Shadow Mario, is activated by a blue neckerchief with Mario's signature mustache drawn on it (in later games starting with , Bowser Jr.'s neckerchief is white and has a drawing of a ferocious mouth instead).

Bowser Jr. was also convinced by his father that Princess Peach was his mother and that Mario had taken her from him, thus setting his plan into motion; by framing Mario, he attempts numerous times to kidnap the princess, who he refers to as his "mama". By the end of Super Mario Sunshine, however, Bowser Jr. reveals that he knew Peach wasn't really his mother, while still expressing a desire to fight Mario like his papa.

Bowser Jr. became a landmark character after Super Mario Sunshine, appearing as a playable character in multiple spin-off games (his first being '), as well as having a recurring role as Bowser's elite soldier in the ' games, where he commands the Koopalings. In several games, he uses a smaller variant of his father's famous Koopa Clown Car, officially named the in . Most notably, he appears in , a remake of Mario & Luigi: Bowser's Inside Story, where he takes center stage as the main protagonist of the newly-added Bowser Jr.'s Journey mode.

Later Mario games would explore more facets of Bowser Jr.'s character. In  and subsequent games, Jr. has been shown to invent and pilot large battle machines of various sorts, such as the Junior Clown Car. He is also able to hack computer systems and transform areas into military outposts with factories as seen in . His mechanical and technological prowess show through in his Super Smash Bros. moveset, which shows him summoning various tools and gadgets from within the Clown Car.  explores Jr.'s personality in further detail, showing that, while he may be the child of a villain, he is ultimately a lonely Koopa who desires friends above anything else. Other games—such as Mario + Rabbids Kingdom Battle, ', and '—show that Bowser Jr. cares deeply about his father.

Bowser Jr. has complicated relationships with the main cast. Despite knowing that Peach is not his real mother, he will still assist Bowser in his attempts to capture and marry her. Peach herself sees Bowser Jr. as a misguided child that needs a proper parent, particularly not Bowser. Though Bowser Jr. is antagonistic for most playable characters, he especially despises Mario for constantly getting in the way. This animosity was strongest in Sunshine where he actively sought to take Mario down. Later installments toned this hatred down, with the two fighting only when their paths cross. Bowser Jr. even occasionally shows a willingness to team up with Mario, albeit only when out of need. When such a mission is complete, he goes right back to his antagonizing ways. While Mario will not hesitate to fight out of self-defense and can sometimes be cold towards him, he has no ill will towards Bowser Jr. and is more than willing to help him whenever their interests are aligned.

In Super Mario Sunshine, Bowser Jr.'s voice is performed by. has provided his voice in later games since .

In Super Smash Bros. Brawl
Bowser Jr. appears as a trophy and as two stickers.

As a playable character
Bowser Jr. was unofficially revealed as a playable character in SSB4 by a leak of the ESRB review video. He was later officially revealed as a playable character on October 23rd, 2014 during the Super Smash Bros. for Wii U 50-Fact Extravaganza, albeit after being revealed upon the release of Super Smash Bros. for Nintendo 3DS worldwide. The seven Koopalings also appear as alternate costumes for him. Bowser Jr.'s color scheme is more monotone compared to his appearance in the series, similar to his father; otherwise, his appearance is unaltered.

Bowser Jr. fights in his Junior Clown Car, which provides him with a wide variety of weaponry based on Mario series hazards to use as attacks; these attacks include dropping Mechakoopas, firing cannonballs, and punching with boxing gloves (inspired by its appearance in New Super Mario Bros. U). Bowser Jr. also attacks for himself in some instances, such as swinging a hammer in his up aerial and while ejected from his Clown Car during his up special move, and hitting opponents with a toy hammer for his pummel. The Clown Car also provides a unique trait: attacks that hit the Clown Car will deal less damage, but attacks that hit Bowser Jr. himself will deal more damage (being the most prominent during his up special). His Final Smash has him briefly transform into his Shadow Mario form, which then swipes the screen with the Magic Brush, creating a large X, which hurts all opponents that it touches.

Currently, Bowser Jr. is placed 48th out of 55 on the tier list, placing him in the F tier. His Clown Kart Dash special gives him a fantastic approaching option thanks to its speed and usefulness in starting combos. He also comes with some powerful finishers that can potentially KO opponents below 100%. Although he's classed as a heavyweight, his aerial game is respectable thanks to his good air mobility and ability to juggle opponents with his aerials. Despite these strengths, Bowser Jr. is held back by notable flaws, such as a laggy grab, poor ground mobility, and his recovery in Abandon Ship! is predictable and open to gimps. Bowser Jr.'s weaknesses hold him back from leaving much impact on the competitive scene, having below average results in tournament, though he still has a few dedicated players.

As a playable character
Bowser Jr. returns as a playable fighter in Super Smash Bros. Ultimate. Like in, Bowser Jr. is an unlockable character.

Trivia

 * Technically, Bowser Jr. is the only fighter to lack alternate costumes; instead, the Koopalings appear as alternate fighters that Bowser Jr. can be swapped out with.
 * Bowser Jr. is the only fighter to not use an alternate costume for his Alt. Trophies.
 * The Koopalings have their own separate trophies, but they do not have Alt. Trophies.
 * Bowser Jr. is also the first fighter to share his roster spot with an opposite gender alternate fighter that is an entirely different character. The second is the Pokémon Trainer in Ultimate.
 * Bowser Jr. is also the first fighter to share his roster spot with an opposite gender alternate fighter, but not have an equal number of male and female alternate fighters. The second is Pikachu in Ultimate.
 * Unlike his father, Petey Piranha, Donkey Kong, Diddy Kong and King K. Rool, Bowser Jr. retains his voice actor from the Mario series. He shares this trait with Yoshi and the Koopalings.
 * He, the Koopalings and Princess Daisy are also the only fighters from the Mario universe to exclusively have used voice clips recycled from outside sources.
 * Bowser Jr. is the only SSB4 newcomer to be unlockable in and a starter character in, due to Ness, Jigglypuff, and Ganondorf being veterans.