Morton Koopa Jr.

Morton Koopa Jr. (known as Big Mouth Koopa in the cartoons, and erroneously called Morton O. Koopa in the Playing with Power: Nintendo NES Classics guide ) is one of the Koopalings, a clan of seven siblings that act as leaders of the Koopa Troop under Bowser (originally considered his children). Morton stands out because of his primarily darker skin coloration and his white head with a star painted on the left side. Morton is named after famed talk show host and singer-songwriter Morton Downey Jr. This is the reason for the "Jr." at the end of his name, which was a point of confusion when he was first introduced as one of Bowser's children. No in-universe explanation of his name was provided at the time, though the editors of the magazine Nintendo Power once claimed that when they asked Bowser why Morton Koopa was called "Jr.", he denied having any sons, then pelted them with Bob-ombs until they left.

Super Mario Bros. 3
Morton made his first appearance in Super Mario Bros. 3 where he, along with his siblings aided their father in an attempt to take over the Mushroom World. At some point, Morton discovered that Mario was capable of accessing transformations, which meant Mario might prove to be a challenge, and likewise reported the discovery to Bowser. Morton usurped the king of Desert Land and took over. He used the same attack pattern as Larry, but in the end he was defeated by Mario.

Morton also uses his wand to shoot magical projectiles. Larry, fought previously before Morton, barely used his wand, as what he mainly did was jump. Morton jumps also, and is a slight bit harder to defeat than Larry.

Morton also appears in Airship's Revenge, an optional bonus World-e level for the GBA remake Super Mario Advance 4: Super Mario Bros. 3. Besides Morton, only two other Koopalings are given e-Reader levels: Lemmy and Ludwig, and until the release of the Wii U Virtual Console version of Super Mario Advance 4, Morton was the only one of the three to be present in both the Japanese and overseas releases of the e-Reader levels. In his level, Morton attacks Mario with a new airship and fights the same way as he did in his original boss battle, complete with wand. After being stomped three times, Morton is defeated once more.

Super Mario World
Morton appeared again in Super Mario World helping his family in an attempt to take over Dinosaur Land. His castle is located in the second area, the Donut Plains. Morton attacks Mario or Luigi by climbing the walls and ceiling of his room and dropping down. Mario or Luigi needs to stomp on his head thrice or shoot a dozen fireballs at him to win. Afterward, Morton's castle was kicked twice by Mario before repeatedly stomped on to cause it to collapse.

Although Morton's official artwork depicts his shell as gray, as with the other Koopalings, his sprites are differently colored: his battle sprites use the green palette intended for the green Koopa Troopas and other lesser enemies, while his cast roll sprite uses the teal palette applied to the Buzzy Beetles' in-game sprites, and resembling Ludwig's palette in Super Mario Bros. 3; although a grey palette closer to his artwork (and his Super Mario Bros. 3 sprite) exists in the game's graphics, for unknown reasons, it is applied to Roy Koopa's cast roll sprite instead, and none of the Koopalings within actual gameplay.

New Super Mario Bros. Wii
Morton appears as a boss once again in New Super Mario Bros. Wii.

In the game's intro, Morton, the other Koopalings, and Bowser Jr. use a giant cake to sneak into Princess Peach's birthday party. They use the cake to capture her and then fly away on their airship with Mario, Luigi, Yellow Toad, and Blue Toad following them from close behind.

Morton is fought in World 6 in his tower on a platform with the ends of each side slightly raised up, set in a sea of lava. When Morton sees Mario, he stamps his foot and growls, then begins to fight.

Morton's main method of attack is shooting pink energy blasts that can be targeted in any direction. He can also do a Ground Pound move similar to that of Roy Koopa or a Sledge Bro, that will stun anybody who is on the ground. His pounds last for less time than Roy or a Sledge Bro. Also, Morton's casting speed is extremely slow compared to Roy, but his magic is the fastest in the game, along with Iggy. Whenever Morton is damaged, he will jump into his shell and spin to attack. This attack is faster than the other Koopalings. Fortunately, it can be easily avoided if the player jumps on the raised ground. However, Skewers will come down from above and land on the two raised platforms, damaging anyone that they hit. Once Morton has been stomped on three times, he will retreat to his castle.

In his castle fight, it appears it is going to be very alike to the attacks Larry used. Then, Magikoopa flies in and sprinkles magic. At first, nothing looks different, except the ground has slightly lowered. Then, Morton will then use his immense weight to ground pound and cause the platforms on either side of him to rise up and hit the ceiling. He will jump around and repeat this tactic throughout the battle. Getting squished will defeat Mario and company in one hit. It is strongly noted that Morton never uses his magic in the castle fight, and he doesn't start spinning around as long as the pillars are up. Also, unlike his tower battle, Morton's Ground Pounds won't stun grounded players during the castle battle.

After being defeated, Morton is later seen along with the other Koopalings getting Bowser back up, only to have Bowser's castle fall on top of all of them.

On a side note, unlike in the past titles, players fight Morton after Roy in this game. Also, in Super Mario Bros. 3, he is the boss of a desert world, while another desert world (though still the second world) is given to Roy in this game, and Morton gets a mountain level instead. In addition, neither Roy or Morton get the cloud level, but it is rather given to Ludwig.

New Super Mario Bros. 2
Morton reappears in New Super Mario Bros. 2. This Koopaling is fought similarly to Roy in the predecessor. He is fought in the castle of World 4 and will stomp his foot and growl at Mario, like he did in the previous game. In his battle, he will create Spiked Balls using his wand during the battle and use Ground Pounds to stun all players that are on the floor. Just like the other battles with the Koopalings the player has to jump on him to defeat him. Unlike the other Koopalings, because of the nature of his "boss fight" with Mario, he doesn't spend a limited amount of time in his shell upon being stomped, as he requires a pipe upon being stomped on to return to his position. After three stomps, Morton is defeated, leaving the key to World 5.

Morton survived the encounter, and rejoined his comrades at Bowser's castle, where they attempted to petrify Mario with their Koopa Clown Car's petrification device. He also aided Bowser alongside the rest of the Koopalings by causing him to grow larger, but it resulted in him and the others being knocked into a lava pit by Bowser due to his increased size. He and the other Koopalings survived, however, and attempted to help Bowser by airlifting him with the Koopa Clown Car, but this resulted in it crashing due to it being unable to handle the combined weight of both them and Bowser. Morton ended up on his back, also attempting to get himself back up but couldn't due to his large size.

New Super Mario Bros. U / New Super Mario Bros. U Deluxe
Morton returns in the Wii U game New Super Mario Bros. U and its Nintendo Switch port as a boss. He is the boss of Layer Cake Desert, much like how he was the boss of Desert Land in Super Mario Bros. 3. Like in Super Mario Bros. 3 and Super Mario World, he is the boss of the second world. Morton is battled in Morton's Compactor Castle. Like Wendy, Lemmy, and Roy, Morton's boss battle involve him using a weapon instead of a magic wand. This time, it is a large hammer that's apparently filled with magic. He will once again stomp his foot at Mario when he sees him before battle. While he still shakes the ground by stomping on it, he'll use his hammer to knock giant Pokey segments in the player's way. He can knock Pokey segments straight at the player or knock them in high arcs. In addition, like most of the Koopalings (except for Roy Koopa and Ludwig von Koopa), Morton also fought the Mario Bros. in the cabin of his ship. Three stomps will have him fall offscreen.

Despite this, Morton survived, and was later picked up along with the rest of the Koopalings by Bowser Jr., although they ended up escaping by hanging onto Bowser's tail after the latter inadvertently destroyed Bowser Jr.'s (already damaged) ship.

Morton has his own personalized airship, with his face on the bow, and his black-colored shell at the deck of the ship. The stern of his ship has a gray color design, similar to his former shell color from past appearances. Like most of the airships, his airship is equipped with a propeller at the back as well as another just beneath the crow's nest. Morton's airship is equipped with four cannons, two on each side, like Roy's ship except that the cannons are placed vertically from each other. There are also grey lids on top of the cannons used for opening and closing the cannons. His airship has the biggest build of all the Koopaling ships. The ship is also made out of a darker wood than the other Airships, a reference to his darker skin tone. The cabin of his ship contains gold-tinted windows, gold Stone-Eye statues at the top of the room and a sand pit elevated on a platform.

When Morton's airship appears at the roof of the castle, his voice sounds different from his usual voice. A similar oddity occurs with Roy's and Ludwig's airships.

New Super Luigi U
Morton Koopa Jr. appears in New Super Luigi U. He is battled in the same way as New Super Mario Bros. U, and is found in Morton's Lava-Block Castle.

Amada Anime Series: Super Mario Bros.
Morton, along with the other Koopalings appeared in two of the Japan-only Super Mario anime videos. In Momotarō, they try to defend their king's castle, only to be defeated by Mario and his friends in their quest to rescue Princess Toadstool. In Snow White, Morton and the other Koopalings play a similar role, once again, being defeated by Mario as he attacks Bowser's Castle.

Super Mario World: Mario to Yoshi no Bōken Land
Morton appeared in the interactive Anime adaptation of Super Mario World. On Chocolate Island, he, alongside Lemmy, Wendy, Larry, Ludwig, and Roy, ambushed Mario and Luigi at a fortress. He alongside his brothers fought Mario after Wendy nearly fell into lava, but was stomped by Mario alongside Roy. Although they got up, Mario by that time broke open a red block to get a Cape Feather and sent them flying.

DIC cartoons
"It's curtains for you creeps! You're history, you've had it, you're done for, it's all over, we win, time's up, your cloak is cleaned! The sun has set, the fat lady has sung, the cheese has molded, the Super Mario Bros. are no more!"

- Morton

In The Adventures of Super Mario Bros. 3 and Super Mario World cartoons produced by Nintendo and DIC Entertainment, he was renamed Big Mouth Koopa (although he was once called "Big Mouth Koopa Jr." on the bonus disc of The Adventures of Super Mario Bros. 3 DVD set released by Shout! Factory, making him closer to his original namesake), ostensibly because he was more talk than action. In fact, he talks so much that someone frequently has to step in to stop his speeches (usually King Koopa or Bully Koopa). He once performed a duet called "Stomp my Name on the Walk of Fame" with Kootie Pie in "Dadzilla".

Aptly, in the Super Mario World cartoon, he occasionally served as an announcer in three episodes: "Send in the Clown", "Rock TV", and "The Yoshi Shuffle". "The Yoshi Shuffle" is Big Mouth's last animation appearance.

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; the star-shaped birthmark on Morton's face is darker around the cheek, while it's just one solid color on Big Mouth. Lastly, Big Mouth is shorter and thinner than Morton, his arms are thinner and a little bit longer, his claws are a little bit sharper and his mouth is light orange instead of pink while his skin is dark orange instead of dark brown. In the Super Mario World cartoon, however, his mouth and skin return to their original colors.

Sometimes, Big Mouth's name is spelled as Bigmouth. He was voiced by Dan Hennessey.

The name "Big Mouth" might be a reference to "Loudmouth", a nickname given to Morton Downey, Jr.

Nintendo Adventure Books
In Leaping Lizards, Morton sneaks into Mushroom Palace, vandalizing the throne room and transforming the Mushroom King into a rabbit with his magic wand. If Luigi decides to run ahead of his friends after hearing what Morton is up to, he can find the Koopaling in the midst of smearing peanut butter on the walls, and gets into a fight with him, acquiring his wand before the Koopaling escapes if the reader makes the right choices. Due to not knowing how to use Morton's wand, and thus left unable to change the king back, Luigi proceeds to track the Koopaling to his houseboat in Water Land and breaks in, prompting Morton to call Iggy and the Doom Ship for backup, only to be abandoned by his sibling when the bespectacled Koopaling spots Luigi. Forced to try and swim for it, Morton is eventually cornered and tipped onto his shell, leaving him helpless, on a small island by Luigi, who learns from Morton that the only way the king can be changed back to normal is with a special silver whistle, which Iggy is later revealed to possess.

Three weeks later, Morton and five of his siblings show up as competitors in the International Mushroom Games, where the first prize is Iggy's whistle, which he won by cheating in last years competition. What events Morton participates in besides the Beetlebowl (an all-team contest) are unspecified.

In Koopa Capers, Morton and his brothers have their wands stolen by Wendy, who disappears with them shortly afterward, intent on overthrowing their father with her own army, and a super wand she plans to create by fusing her own wand with her brothers'. If Luigi, who had been coerced by Bowser into searching for Wendy, tracks the female Koopaling down to her hideout, Bowser and the male Koopalings, who had been following him, will barge in after the plumber, but decide to stave off punishing Wendy for her mutiny if she helps search for the hiding Luigi. If Luigi had acquired Boom Boom's socks earlier in his adventure, he can toss them into Wendy's simmering wand combination potion, which will release fumes that knock the entire Koopa family and their minions out for at least a week. During a point where Wendy O. Koopa was about to attack Luigi, a small picture that was supposed to show an angry Wendy O. Koopa mistakenly had a picture of Morton Koopa Jr. instead, even though he was not in that particular scene.

At an unknown point in Brain Drain, Morton's mind ends up in Toad's body due to Iggy's Synapse Switcher. When Luigi's mind is transferred to Princess Toadstool's body, Morton (who is unaware of the change) tries to trick Luigi into following him to a secluded houseboat by promising him "triple decker lasagna and chocolate chip raviolis". If Luigi tells Morton who he really is, Morton immediately tries to attack him, but Luigi escapes by using the princess's floating ability to cross the nearby Dinosaur Lake. If Luigi instead decides to pretend to be the princess and take Morton up on his offer of snacks, he will be taken to the houseboat, and be ambushed by a group of Koopa Troopas, leading to a Game Over.

Mario is Missing!
Though Morton doesn't appear in Mario is Missing!, his picture is used in the SNES version's manual. In addition, unused quotes attributed to Morton can be found in the original DOS version, suggesting that he was originally planned to be encountered in-game as well.

Yoshi's Safari
In Yoshi's Safari, Morton helps his family invade Jewelry Land and steal the jewels that maintain the stability in the kingdom. Bowser entrusts one of these jewels to Morton, who then watches over the area known as Spirit Mountain. He attacks in a giant, blue, mechanical frog, but Mario and Yoshi defeat him with the aid of the Super Scope.

Hotel Mario
In Hotel Mario, Morton is the first Koopaling to be fought by Mario and Luigi. He was given the treetop Wood Door Hysteria Hotel to run when the Mushroom Kingdom was once again taken over by Bowser. Here, he held Princess Toadstool captive for a short while, but soon became the first Koopaling battled. At Morton's Tree House o' Pain, he had little defining characteristics. He will wander around open any doors; however, if he finds Mario or Luigi inside an elevator, he will step inside for a moment, then step out and spit the ill-fated plumber's cap on the floor. Fortunately, the Mario Bros. were able to move on.

Mario & Luigi: Superstar Saga / Mario & Luigi: Superstar Saga + Bowser's Minions
The Koopalings reappeared in Mario & Luigi: Superstar Saga where they guard Bowser's Castle. Morton is the second Koopaling to be fought. Defeating Morton raises a platform, allowing the Mario Bros. to continue on towards Lemmy Koopa.

To get to Morton, Mario and Luigi will have to jump over shockwaves he sends towards the two. High Jumps and Spin Jumps will not work. In battle, Morton has two attacks, sending shockwaves and spitting fireballs at the target (like all the other Koopalings).

Morton appears in the remake Mario & Luigi: Superstar Saga + Bowser's Minions with the same role as before and added dialogue. His shockwave and fireball attacks have been modified slightly: he will send an extra shockwave after pounding the ground, and in addition to spitting fireballs at Mario and Luigi individually, he can also spit two fireballs that target both of them at once. These fireballs will bounce on the ground once before landing on Mario and Luigi.

He also appears in the added on alternate story mode Minion Quest: The Search for Bowser as a Melee-type ally. He and the other Koopalings get brainwashed by Fawful in the beginning of the game’s story and try to conquer the Beanbean Kingdom afterwards. Morton is requited after the player defeats him in the Teehee Valley.



Mario & Luigi: Paper Jam
"Bwahahaha! I'm gonna stomp 'em silly!"

- Morton

Morton reappears in Mario & Luigi: Paper Jam. He is first seen with Iggy, Lemmy and King Bob-omb on top of Mount Brrr, where they shower the land with new enemies and terrain with the help of cannons. In Bowser's Castle, Morton alongside Lemmy command the Papercraft King Boo, which they use to battle Mario & co., but are soon quickly defeated. He is then seen in Neo Bowser Castle, where he attempts to stop the Mario gang from obtaining one of the Fire Ores needed to create Papercraft Fire Mario. Later on in Neo Bowser Castle, after Mario and co. create the bridge leading to the Bowsers, he appears at the end of the bridge with Iggy and Lemmy, telling them to hurry up and push the button in order summon a large cannon that is aimed at Peach's Castle. At the end of the game, on top of Neo Bowser Castle, Morton is encountered one last time along with the rest of the Koopalings, where he is fought alongside Lemmy and Iggy. In his battle, he can mess up the bros' battle cards, making them do effects that are unknown to the player. After Lemmy and Iggy get dizzy from their own attacks, Morton attempts to get back at the Mario Bros. by lifting Iggy's Chain Chomp and throwing it at them. Mario and Luigi must use Paper Mario as a trampoline to bounce the Chain Chomp back to Morton. Failing to do so will result in an instant Game Over. Successfully bringing the Chain Chomp back to Morton will cause damage to him and leave him dizzy. He remains dizzy until it is his turn to attack again if he hasn't been defeated. After the battle, Morton utters some last words, where he tells Bowser to forgive them for failing to defeat Mario and the others before exploding.

Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey


Morton appears in the game's new side story. He was the only Koopaling to remain by Junior's side until his brainwashment after being fed Malotone Formula :X by the Best Fitness Friends. Before then, he also demanded for the Omega-Onion from an Oho Jee in an argument that humorously lasted half an hour. Of all the Koopalings, Morton's relationship with Junior was developed in this story, which served a purpose to Junior's change of attitude towards his allies.

During the festivities by the Koopa Corps. regarding their victory against Fawful's forces, Morton and Bowser Jr. proceeded to feast on some meat.

Mario Kart 8 / Mario Kart 8 Deluxe
Morton Koopa Jr., alongside the rest of the Koopalings, appears as a playable character for the first time in Mario Kart 8, where he is an unlockable character. In this game he is voiced by David Cooke. His nickname in a Japanese Nintendo Direct for Mario Kart 8 is ｢無敵のタフガイ」, or "Unrivaled Tough Guy'" (localized as the "Mass of Muscle" or "Invincible Tough Guy" ). His emblem is a white silhouette of his head on a black background in a similar way to Bowser's emblem.

Morton is the heaviest Koopaling in the game, with his greatest strengths being his speed and weight tied with Wario, Bowser, Dry Bowser, and the Large Mii. His other stats can potentially drop to the lowest possible levels, however.

Morton is the Normal Staff Ghost for Bone-Dry Dunes. Various advertisements and references appear in some of the tracks in the game for Morton Construction.

Morton's main colors for his Standard parts and Pipe Frame are white and grey, and his secondary color is green. The color scheme selection of his other parts is based on his signature black, making it nearly identical to that of Black Miis. An exception to this is his GLA, which is white.

Morton reappears in Mario Kart 8 Deluxe, the Nintendo Switch port, sharing stats with only Bowser and large Miis. He is also now available from the start.

Super Smash Bros. Brawl
Although Morton himself does not appear in Super Smash Bros. Brawl, he is referenced in the form of Bowser's white palette swap, which is based on Morton's original design.

Super Smash Bros. for Nintendo 3DS / Wii U
Morton (alongside the other Koopalings) makes his Super Smash Bros. debut as a playable character accessible via Bowser Jr.'s alternate costumes in Super Smash Bros. for Nintendo 3DS and Super Smash Bros. for Wii U. He is unlockable in the former game and available from the start in the latter. His attacks and statistics are identical to Bowser Jr.'s, though he is referred to by his own name by the announcer and has his own voice clips. Morton can also appear in place of Bowser Jr. in All-Star mode (like the other Koopalings). It should be noted that the rings circling the spikes on his shell are a darker shade of grey compared to his previous appearances.

Like the other Koopalings, he is actually driving a mass-produced version of the Junior Clown Car (as noted by the yellow light bulbs that serve as its eyes). The rim and propeller of his Junior Clown Car are colored black (his signature color), and he also reuses his voice clips from his appearance in New Super Mario Bros. Wii, thus he is voiced by Lani Minella.

The title given to Morton in the Boxing Ring is "The Enforcer" (NA) or "He'll Make You See Stars" (PAL) in the Wii U version.

Besides his role in the game, Morton's likeness, or more accurately, his pre-New Super Mario Bros. Wii design, acted as the basis for Bowser's gray palette swap in the same game.

Super Smash Bros. Ultimate
In Super Smash Bros. Ultimate, Morton (alongside the other Koopalings) returns as a playable character accessible via Bowser Jr.'s alternate costumes. He is once again an unlockable character, like in Super Smash Bros. for Nintendo 3DS. Just like in the previous game, his attacks and statistics are identical to Bowser Jr.'s, though he is referred to by his own name by the announcer and has his own voice clips. Unlike in Super Smash Bros. for Nintendo 3DS / Wii U, all seven Koopalings (Morton included) now use their magic wands for any occasion where Bowser Jr. would use his hammer. These occasions include all corresponding attacks, their side taunt, and one of their victory poses.

Puzzle & Dragons: Super Mario Bros. Edition
Morton appears in Puzzle & Dragons: Super Mario Bros. Edition as a Fire attribute character. He's the World 3-Castle and World 3-Airship Boss. Morton will join the player when ★World 3-Airship is completed. His Skill is Morton's Flame, which changes Water Orbs into Fire Orbs and Heart Orbs into Wood Orbs.

Paper Mario: Color Splash


Morton makes his Paper Mario series debut in Paper Mario: Color Splash. In this game, he has stolen the red Big Paint Star. He is encountered at the top of The Crimson Tower and acts as the game's first boss. In combat, he uses his magic wand transformed into a large wooden hammer. In the first part of the battle, Morton stays on a pedestal taken into battle by two Shy Guys, that also aid him in battle, and retreats on his shell as Mario attacks. While on the pedestal, Morton can attack by slamming on the ground, creating a shockwave that deals 4 HP of damage and inflicts the Crumpled status effect if not blocked. After the pedestal is blown away by Mario's hammer, Morton directly attacks Mario with the hammer, dealing 8 HP of damage, or by spinning his shell, dealing 12 HP of damage, then, after a while, he calls for two Shy Guys who bring another pedestal in battle and fight with him. Once Morton has received enough damage, he sets his hammer ablaze, drastically increasing its attack power to 48 HP. The fire can be put out using a fire extinguisher Thing card, that leaves only the grip of the hammer intact, decreasing its attack power to 1 HP. Upon being defeated, Morton will allude to his Master ordering him to steal the red Big Paint Star, causing Huey to deduce that someone else was indeed searching for the Big Paint Stars. In the Japanese version upon being defeated, Morton instead says 「おかた」, which translates to this gentleman, which was presumably done to avoid giving away that Bowser, or rather, Black Bowser had been behind the theft of the Paint Stars before his formal debut.

Through hacking, it is shown that even with powerful cards, the player cannot beat Morton without the fire extinguisher, as his HP will not go down after a certain point.

Unlike in Mario & Luigi: Paper Jam, Morton speaks in a simple, loud and unintelligent manner similar to Lava Piranha from the first game. He also often doesn't realize what is happening until he stops for some seconds to think. Furthermore, like other paper characters, he has black eyes instead of grey eyes.

Other appearances
Morton was originally going to appear in Super Princess Peach, although he was taken out of the final game with the rest of the Koopalings. In the unused sprites, his and Roy's shells are noticeably green instead of their usual black and pink coloration, respectively.

In Mario & Sonic at the London 2012 Olympic Games, the player can unlock a Mii costume based off of Morton's design. Once the player dons it, they will inherit Morton's traits and stats. This is true for the rest of the Koopalings.

In the Super Mario Mash-Up Pack in Minecraft, Morton Koopa Jr. appears as a playable skin along with the rest of the Koopalings.

Morton is included (along with the other Koopalings) as a Boss in the Boss Deck of Monopoly Gamer. He is the second Boss in the deck.

While Morton and the other Koopalings do not appear in Mario Tennis Aces, their airships can be seen in the background of the Savage Sea court.

Physical appearance
Unlike the other Koopalings, Morton has a dark brown skin tone, except for his face, which is white. He also has a unique star mark (although Larry now has a similar marking) on the left side of his face which is centered on his left eye and covers part of his snout and cheek. This is evocative of the makeup of famous rock band KISS, specifically Paul Stanley, a.k.a. "The Star Child". Morton has four, fang-like teeth in the upper corners of both sides of his large mouth; they are the same as Iggy's. He also has a four-ribbed, light, plated belly and a single tan-colored pad on each foot. His shell is black, lined with a white encasing, and the multiple, short, spikes are circled with light grey rings.

He has small, circular-shaped gray eyes, like Ludwig's. He has a round head and a large and burly body, making him both taller and broader than most of his siblings. According to Bowser Jr., Morton was big-boned, thus explaining his more burly appearance. Morton appears to be relatively hairless, except for three, thin, long, black hairs at the top of his head. He also has three-haired black eyebrows that extend off his face like Wendy's. Morton wears the same metal, spiked, cuffs as the other male Koopalings. In the Super Smash Bros. series, Morton's appearance is unaltered compared to most Mario characters, including Bowser. In Super Smash Bros. Ultimate, however, Morton receives a slightly darker and subdued color scheme, while his hair, spikes, and shell receive simple detailing, though his scales remain undefined. This trait is shared with Bowser Jr. and the other Koopalings.

Development
Part of Morton's body could be seen in the sketch made during the redesign of Bowser for the Family Computer Disk System version of Super Mario Bros.: The Lost Levels, showing Morton's head being similar to the current one, including the shape of the mouth and the star on the left eye. Differences with respect to the current design include two protruding teeth instead of the current four, two-haired brows instead of the current three-haired ones and two hairs instead of the current three. The claws in the toes also weren't as visible as they currently are. A more notable difference, though, is Morton's size: in the sketch Morton was shown to be about as tall as Toad and the body proportions showed him being younger, with the head proportionally being bigger with respect to the rest of the body.

His redesign in New Super Mario Bros. Wii marginally changed his appearance, with his shell becoming darker, lined with a grey encasing instead of the previous yellow one and featuring light grey rings around the spikes. The pads under his feet also became tan colored just like the pads of the other male Koopalings, while before their color was distinct. Finally, Morton's irises became visible, revealing their grey color and his tail became visible as well in hand-drawn and artwork illustrations, while previously it was visible only in the sprites of the games.

Personality and traits
Even though according to the trophy of the fourth installment in the Super Smash Bros. series Morton is proudly more brawn than brains, similarly to Roy, the Japanese Super Mario Bros. 3 manual implies that he is astute enough to realize whether there are any possible setbacks regarding defeating Mario and can likewise report the information to Bowser. Furthermore, in Mario & Luigi: Paper Jam, when Iggy and Lemmy are eager to fight the Mario Bros., Morton reminds them that they had just wiped out Wendy, Larry, Ludwig, and Roy beforehand. The English translation of the Super Mario Bros. 3 manual instead tones down his thoughtful wording and makes him seem angry, a trait confirmed in the Nintendo Player's Guide for Super Mario Advance 4, in which Morton is said to be a grouch with a cantankerous personality. Morton may have an interest in construction, as in Mario Kart 8, there are advertisements for "Morton's Construction" with Morton's face on it. Curiously, in Ice Ice Outpost many containers and machines present the Morton or Morton Construction logo on them, suggesting that his company is collaborating with the Toads of the Toad Polar Expedition 2014-2015. Along with construction, one of his stunts include him flexing his muscles, which indicates that he likes showing off his strength. This latter trait, along with the preference of brawn over brains, is exacerbated in Paper Mario: Color Splash, in which he boasts about his strength and weight while talking in an unintelligent, loud and simple manner, such as saying "MORTON STRONG! MORTON MORE TONS!". In Mario & Luigi: Superstar Saga + Bowser's Minions, Morton is always shouting and often speaks in the third person, but his sentences are more complete and concise. In Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey, Morton is again depicted as being unintelligent like in Minion Quest: The Search for Bowser, with the Best Fitness Friends jokingly stating that he has 10 brain cells. Regardless of his intelligence or lack thereof, however, he still possessed a strong will like the other Koopalings, as Fawful was forced to use a maximum dosage of his brainwashing spray to bring him under his command, and in Bowser's Inside Story, he resisted the effects of Malatone:X long enough to attempt to warn Bowser Jr. to flee from him due to knowing he can no longer control himself. It's also implied that he was a bit of a bad cook, as when offering Bowser Jr. a piece of meat, he mentioned that while Morton was strong, "Fire stronger", and Bowser Jr. was reluctant to eat it.

In the Mario & Luigi series, Morton showed loyalty and protectiveness to his comrades and the Royal Koopa family. This was first shown in Mario & Luigi: Paper Jam, with Iggy and Lemmy left disabled from their own attacks on the Mario Bros. that backfired on them, and Morton declaring his intent on avenging them. It was explored further in Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey, particularly with his relationship with Junior. Upon given the order to look after Junior by Bowser, Morton took his role as a protector seriously, keeping the Koopa prince happy by feeding him his favorite food, and even one of his skills as First Officer is placing himself in front of Junior, acting as a shield. Morton puts Junior's safety as priority and would fight anyone who has intentions of harming him, even from one of his own siblings, shown when he got in between Roy and Junior when the latter two were arguing.

In The Adventures of Super Mario Bros. 3, all the Koopalings were given names to match the personalities they were given and such was the case with Morton, whose name was changed to Big Mouth Koopa. Big Mouth was extremely talkative, to the point of never seeming to know when to stop talking, which continuously forced Roy to interrupt him. According to the bio on the DVD set for The Adventures of Super Mario Bros. 3, he was also extremely arrogant in regards to his intelligence, as well as exceptionally ignorant regarding the actual facts of the world, and he never accepts responsibility for being wrong, preferring to blame others instead. In addition, he was also known to make cutting remarks, which were severe enough to even make his father cry if directed at him.

Unused lines for Mario is Missing!, which would have been used for a planned boss battle against Morton, implied that he was largely sarcastic and wise-cracking.

Powers and abilities
Like Roy, Morton is one of the strongest Koopalings, using his weight to try and crush Mario or paralyze him by using a powerful ground pound, as in Mario & Luigi: Superstar Saga and Super Mario World, which even involved him running up the walls and dropping down from the ceiling. His debut appearance in Super Mario Bros. 3 did not involve his earthquake-causing power, however, and he relied on the standard abilities shared with his siblings to fight, such as jumping and shooting magic blasts, although he generally doesn't use his magical abilities as much as his siblings. In New Super Mario Bros. Wii, he tended to use his magic wand once his enemies were already immobile, and the game also showed that he couldn't actually jump very high, unlike earlier depictions. He also has the ability to shoot spiked balls from his wand, as shown in New Super Mario Bros. 2. In New Super Mario Bros. U, he has a magic hammer that he uses to knock giant Pokey segments at the player. Like the other Koopalings, Morton can breathe fire, and in Mario & Luigi: Superstar Saga, he used some sort of sonic screech against the Mario Bros., which is like Bowser Jr.'s Sonic Roar! Super Ability from Mario Strikers Charged. His bio on the Japanese New Super Mario Bros. Wii website also implies that Morton's strength is dependent on his weapon. In Mario & Luigi: Paper Jam, Morton also was demonstrated to have a degree of superhuman strength, as he was shown effortlessly lifting and hurling a massive Chain Chomp at the Mario Bros. in an attempt to avenge Iggy and Lemmy. In Super Mario World at least, he was also shown to be somewhat athletic, as he was able to run up a wall and on the ceiling before striking a pose when landing.

Despite his strengths, his size also resulted in him being unable to get up once he is forced onto his back, as evidenced by the ending for New Super Mario Bros. 2, where he ended up on his back as a result of the Koopa Clown Car crashing.

Sprites relating to his planned appearance in Super Princess Peach implied that he would have inflated himself like a balloon at some point during the battle, as well as spit objects out and charge at her.

Super Mario Bros. 3 Nintendo Power Strategy Guide
Morton Koopa Jr.

Grouchy old Morton waits for Mario in his Airship over the Desert Land.

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.

Perfect Edition of the Great Mario Character Encyclopedia
「モートン 種族　王族 性格　落ち着きがない 登場ゲーム　３、ワールド さすがクッパ一族！超重量級だ クッパファミリーの一員で、頭に３本の毛が生えているのが特徴. マリオワールドでは、中ボスとして、ドーナツ平野の城を守っている. 重量を生かしたクッパ系らしい攻撃を特徴としている. 」

Morton Species: King Tribe Disposition: Never calm Appears in: 3, World ''As Expected from the Bowser Family! An Extreme Heavyweight'' ''A member of the Bowser Family who has the trait of growing three hairs on his head. In Mario World, he guards the Donut Plains castle as a mid-boss. His attacks are appropriate for a member of the Bowser Group who knows how to use his weight.''

「光線攻撃に気をつけろ マリオ３ではモートンはつえから、光線を３発ずつ発射してくる. 発射のタイミングをうまくはずして、踏みつけるようにしよう. 」

Be Careful of the Beam Attacks ''In Mario 3, Morton fires beams from his wand in groups of three. Carefully avoid the timing of the beams and stomp him.''

「モートンが落下した直後が狙い目！ ワールドでは壁づたいに天井に上がり、マリオめがけて落下してくる. 落下の瞬間ジャンプでよけて、その直後に頭を踏みつけよう. 」

Right After Morton Falls is your Chance! ''In World, he climbs the wall up to the ceiling, then comes falling down aimed at Mario. In the moment when he falls, jump to avoid him, then immediately stomp his head.''

「モータン パワフル！」

Morton Powerful!

「モータン クッパ大王の７人の子どものひとり. 砂漠の国やドーナツ平野の城にすんでいる. ジャンプ力が強く、魔法のつえから、射程距離の長いワッカ光線を発射する. マリオを金しばりにする攻撃がとくい. ★登場作品：３ワ」

Morton ''One of Great King Bowser's 7 children. He lives in Desert Land and the castle of Donut Plains. His jump power is strong, and he fires long-range ring beams from his magic cane. His attack to immobilise Mario is unique.'' ★ Appears in works: 3 Wa

Prima Super Mario Advance 4: Super Mario Bros. 3 Guide
Morton Koopa Jr. 

''Morton Koopa looks a lot more ferocious than the nerdy Larry, but this Koopaling is just as inoffensive in the combat zone, and he succumbs to 10 fireballs or three head stomps. However, the undulating ground could cause you conundrums, so don’t get caught in a corner! Morton is based at the end of Desert Hill.''

Super Mario Advance 4: Super Mario Bros. 3 Nintendo Power Strategy Guide
Morton Koopa Jr.

Cantankerous old Morton has taken up residence in an airship hovering somewhere over Desert Hill.

Mario & Luigi series
Minion Quest: The Search for Bowser/Bowser Jr.'s Journey bio: ''One of the seven notorious Koopalings. Moves slowly, but just one attack can break through rock.''

New Super Mario Bros. Wii Official Japanese Website
「モートン パワーを武器に、力まかせな攻撃をしてきます. 大きな柱には要注意!」

Morton ''Using raw power as a weapon, he attacks with all his strength. Pay special attention to his big pillars!''

Mario Kart 8

 * Weight Class: Heavy
 * Stats
 * Speed
 * Ground: 10
 * Water: 10
 * Air: 10
 * Anti-Gravity: 10
 * Acceleration: 0
 * Weight: 10
 * Handling
 * Ground: 0
 * Water: 0
 * Air: 0
 * Anti-Gravity: 0
 * Traction: 0
 * Mini-Turbo: 0


 * Bio: "Morton’s the biggest of all the Koopalings, and he’s not afraid to throw that weight around. One of the Cruisers in the game, Morton’s got serious Time Trial potential for those willing to practice wrangling him around the track."


 * Staff ghost time

Trophy
Blue indicates exclusive to the Wii U version.

Palutena's Guidance (Wii U version only)
Palutena: That's one of the Koopalings, Morton Koopa Jr.

Pit: ''Hmm. The resemblance to Bowser Jr. is strong.''

Palutena: That Koopa Clown Car is the mass-produced type.

Pit: I guess as heir to the throne, Bowser Jr. would get preferential treatment.

Viridi: The relationship between Bowser and the Koopalings is a real mystery.

Pit: I kind of feel bad for them.

Palutena: That's sweet of you but not very conducive to taking them down, Pit.

Encyclopedia Super Mario Bros.
「モートン

クッパ七人衆のひとり. 七人衆でもっとも大きな体を持つ. 」

Morton

'' One of the Koopalings. He is the largest of the seven.''

Super Mario Pia
「モートン

クッパ7人衆のひとり. 唯一、体の色が茶色で左目のまわりに星形のマークが描かれている. 」

Morton

''One of the Koopalings. Uniquely, his body is brown and a star-shaped mark is drawn around his left eye.''

Quotes

 * "Wah-hoo! Yeah!" - Mario Kart 8 (winning 1st place)
 * "How ya like that? I messed up your battle cards! Go ahead and cry about it. I'll wait!" - Mario & Luigi: Paper Jam
 * "SMART MINIONS JOIN ME. DUMMIES GET BEAT UP." - Mario & Luigi: Superstar Saga + Bowser's Minions
 * "BAD MARIO FIND PAIN STAR! BUT MORTON FIND IT MORE! MORE MORTON'S! MORE TONS! MORTON CRUSH MARIO!" - Paper Mario: Color Splash
 * "…MORTON COOK WITH FIRE. MORTON STRONG! BUT FIRE MORE STRONG." - Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey

Trivia

 * Even though Morton Koopa Jr. is considered the largest and heaviest Koopaling as depicted in Mario Kart 8 and Encyclopedia Super Mario Bros., his jumps in Super Mario Bros. 3 do not cause the ground to tremble, unlike Roy Koopa and the lighter Ludwig von Koopa. He is able to do this in later appearances, though in New Super Mario Bros. Wii, they're still less powerful than Roy's.
 * Morton is the only Koopaling that is fought/listed in all orders as a single boss and playable character: he is the first Koopaling fought in Hotel Mario and Paper Mario: Color Splash; the second boss of Super Mario Bros. 3, Super Mario World, Mario & Luigi: Superstar Saga, New Super Mario Bros. U, and New Super Luigi U; the third boss in Puzzle & Dragons: Super Mario Bros. Edition; the fourth boss in Minion Quest: The Search for Bowser and New Super Mario Bros. 2, not counting Worlds Mushroom and Flower; the fifth boss of Yoshi's Safari and the fifth alternate "costume" of Bowser Jr. in Super Smash Bros. for 3DS/Wii U; the sixth boss of New Super Mario Bros. Wii; the seventh and last Koopaling listed in Mario Kart 8 and the last Koopaling fought in Bowser Jr.'s Journey.
 * Morton Koopa Jr. is the only Koopaling to be portrayed by both female and male voice actors.