Bowser Jr.
Bowser Jr. was the main villain in Super Mario Sunshine, in which he used an alter ego known as Shadow Mario (shown to the left) to frame Mario for vandalizing Isle Delfino using his magical brush made by Professor E. Gadd. He has since then appeared in Mario Kart: Double Dash!!, Mario Power Tennis, Mario Superstar Baseball, and Mario Golf: Toadstool Tour, the last of which inexplicably features his alter ego, Shadow Mario, as well.
In Super Mario Sunshine, Bowser Jr. was shown as covering his face with a drawing of Mario's distinctive nose and moustache (as pictured), presumably for his role as Shadow Mario. In future appearances however, this is replaced with a drawing of a set of fangs, which he can wear over his mouth — as it is in Mario Golf: Toadstool Tour and Mario Power Tennis — but is often shown as hanging loosely from his neck — as in Mario Kart: Double Dash!! and Mario Superstar Baseball. He only has one small fang at the top of his mouth, and presumably he can use these images of fangs, when needed, to make himself look more menacing, and more like his dad.
Bowser Jr. is often confused with Baby Bowser, who appears in Super Mario World 2: Yoshi's Island, Yoshi's Story, and Mario & Luigi: Partners In Time. (Indeed, the character model for Baby Bowser in Mario & Luigi: Partners In Time is virtually identical to that of Bowser Jr., making it even more confusing for the uninitiated.) This character, however, is the infant form of Bowser, rather than a child of his.
Other characters that seem to be similar to Baby Bowser or Bowser Jr. have appeared in the Mario Party games under the names "Mini Bowser," "Baby Bowser", "Koopa Kid" and "Bowser's Cohort." However, these games, created by Hudson Soft, don't follow the plotline of other Mario games, and the Bowser-related characters have larger horns.
Bowser Jr. has yet to appear in a game with any of his siblings, such as Mario and Luigi: Superstar Saga. Therefore, some have theorized that he is a young Ludwig, who remains unnamed so that he would not seem like a "favored" Koopaling. However, the scene in Super Mario Sunshine where FLUDD analyzes Mario shows images of past games, including the fight between Mario and Iggy in Super Mario World, which indicates that Sunshine takes place after World, and therefore Bowser Jr. could not be one of the original seven Koopalings.
