Morton Koopa Jr. is the third youngest of Bowser's eight children.
He is of a stockier build, but isn't quite as powerful as some of his elder siblings, like Ludwig and Roy.
He, along with his other brother Larry, has an odd star-shaped birthmark on his head.
Morton is named after singer Morton Downy Jr.
Super Mario Bros. 3
Morton made his debut in Super Mario Bros. 3 where he, along with the rest of the koopalings,
aided their father in an attempt to take over the Mushroom World.
Morton annexed the Desert Land and used his magic wand to transform the land's sultan into a helpless creature.
In the end, he was soundly defeated by Mario, which broke the curse and turned the sultan back to normal.
Super Mario World
Morton reappeared in Super Mario World. Here He aided his family in conquest once more, this time of Dinosaur Land, the home of the yoshis.
Morton settled in Donut Plains, the second region of the land and would stay there until Mario arrived and defeated him yet again.
In Yoshi's Safari, Morton was in the possession of a stolen jewel, entrusted to him by Bowser for safekeeping.
He was the boss of Spirit Mountain and drove around in a blue, giant mechanical frog built by Iggy. Morton ultimately failed his duty when Mario and Yoshi defeated him with the aid of a Super Scope.
Mario & Luigi: Superstar Saga
Morton and the rest of the koopalings did not play a major part in Mario & Luigi: Superstar Saga.
Morton appeared only at the end of the game where he fought against the Mario brothers, believing Bowletta to be his father.
In this game, Morton had the ability to create shockwaves. However, he was no match for the Mario bros. who defeated him once again.
New Super Mario Bros. Wii
In Super Mario Bros. Wii, Morton along with the rest of the Koopalings caused mischief at Princess Peach' birthday party.
They end up kidnapping her, and gets chased by Mario, Luigi and a couple of other birthday attendants. Compared to the other games he is fought relatively late, having made it all the way to World 6.
In the first fight against Morton, He uses his wand to send out energy blasts, and can do a Ground Pound that will stun all of which are currently located on the ground.
The second fight, which takes place in Morton's castle, is considerably easier. When He does the ground pound, the platforms on either side of him will rise up and hit the ceiling. He will then start to jump around a lot. If he manages to stomp on either Mario or his companions in this state, they will be defeated in one hit. Later on after the credits, Morton and his siblings helped Bowser by pushing him up.
- In the animated series, he is known as Big Mouth Koopa Jr. or Big Mouth Koopa.
- In the Super Mario World TV show, he is served as the announcer in 3 episodes: "Send in the Clown", "Rock TV", & "The Yoshi Shuffle".