Morton Koopa Jr.

Morton Koopa Jr. is one of Bowser's eight children and is the sixth oldest Koopaling. Although he has a large build, Morton doesn't appear to be as powerful as some of his other large brothers, like Ludwig or Roy. This may just be due to the fact that he is one of the younger Koopalings, and needs to grow some more.

Unlike his siblings, many of Morton's features are unique, and are not shared traits. He is the only Koopaling to have brown skin, whereas the others all have orange skin. Morton is also the only one of his siblings to have a unique shell color. While his siblings have either green or pink shells, only Morton has a gray one. He is also the only one to have a white head. Another unique feature of Morton's is the large, star-shaped birthmark on the left side of his face.

History
Morton's first appearance was in Super Mario Bros. 3 where he, along with his siblings (minus Bowser Jr.) aided their father in an attempt to take over the Mushroom World. Morton usurped the sultan of Desert Land and took over, but in the end he was defeated by Mario. Morton appeared again in Super Mario World helping his family in an attempt to take over Dinosaur Land, here he had taken over Donut Plains and attacked Mario by climbing the walls and ceiling of his room and dropping down. Morton was defeated but still helped his family in causing chaos in Hotel Mario, Yoshi's Safari and Mario is Missing!, but after all these adventures Morton along with the other six original Koopalings disappeared. Morton and his bros. and sis reappeared in Mario & Luigi: Superstar Saga were they guarded Bowser's Castle, here Morton learned a new attack, sending shockwaves. Despite this new attack Morton ended up being beaten and has once again disappeared.

Some unused sprites of Morton were found in Super Princess Peach which has spread speculation that the Koopalings were going to appear in it. 1:

Personality
Unlike the other Koopalings who's personalities have been mentioned or hinted their has currently been no word on Morton's personality. Though in the cartoon he was quite talkative and never seemed to know when to stop talking. Which could be his game personality as his names comes from Morton Downey Jr. who's symbol was his big mouth.

Cartoons
In The Adventures of Super Mario Bros. 3 and Super Mario World cartoons he was renamed Big Mouth Koopa Jr. (although the "Jr." part was only mentioned on the bonus disc of The Adventures of Super Mario Bros. 3 DVD set released by Shout! Factory), ostensibly because he was more talk than action. Aptly, in the Super Mario World cartoon, he occasionally served as an announcer. There are a few physical differences between Morton and Big Mouth: Morton's shell is gray and in the Super Mario Bros. 3 cartoon, Big Mouth's is purple; Big Mouth has much larger eyes and purple eyelids; and the star-shaped birthmark on Morton's face is darker around the cheek, while it's just one solid color on Big Mouth. Big Mouth's rambles were given by Dan Hennessey. Sometimes, Big Mouth's name is spelled as Bigmouth.

Name Controversy
The fact that Morton's name ends in a "Jr." has made some fans wonder if Bowser's actual first name is "Morton" as well. This is not the case. This curious nominal suffix is merely a nod to Morton's namesake, just as the "von" in Ludwig Von Koopa is a nod to Beethoven. Morton is named after Morton Downey Jr.. Any speculation into other possibilities of brown-skinned Morton being adopted into the yellow-skinned Koopa family, for example Jr. has no basis in Nintendo canon, as Nintendo has never opined on the issue, one way or the other. In fact, the editors of the magazine Nintendo Power once claimed that when they asked Bowser why Morton Koopa was called "Jr.", he responded by pelting them with Bob-ombs. Some people say that Bowser's Father's name was Morton Koopa Sr... This might be true or just a rumor.

One possibility is that Morton is Bowser's middle name, and Morton Jr. goes by this to avoid confusion.

Bio from The Adventures of Super Mario Bros. 3 Writers Bible
''Big Mouth just can't stop blabbing, and his twisted talent is insult. His cutting remarks can even reduce his father to tears. Big Mouth's got a chip on his shoulder the size of the Doomship. He would never admit he was wrong, even though he usually is. He thinks he knows everything about everything, but what he knows is all wrong, and he always blames the other guy for his mistakes. Big Mouth loves to stir up trouble, and has a needling probing attitude that always gets it. He holds grudges against the whole world.''