Baby Luigi

"Uh-oh, Baby Luigi time!"

- Baby Luigi

Baby Luigi is the infant form of Luigi. In the Yoshi's Island series, he is kidnapped several times by Kamek, where Yoshi, who is protecting Baby Mario, is required to rescue him. Besides the Yoshi series, he has appeared as a playable character alongside his older self in various spin-off titles such as the Mario Kart series, as well as being one of the major protagonists of Mario & Luigi: Partners in Time. He is voiced by Charles Martinet, as with his adult counterpart, Mario, Baby Mario, and other characters.

Adult Luigi has been portrayed as an infant in other media, namely in The Adventures of Super Mario Bros. 3 episode Toddler Terrors of Time Travel‎ and the Family Album "The Early Years" comic, though the Baby Luigi character is considered a distinct entity from these forms.

Super Mario World 2: Yoshi's Island
Baby Luigi appears with Baby Mario during his debut in Super Mario World 2: Yoshi's Island (and its remake Yoshi's Island: Super Mario Advance 3) when he and the Stork carrying him are captured by Kamek and taken to Bowser's Castle. After he is rescued by Yoshi and Baby Mario, the stork safely delivers Baby Mario and Baby Luigi to their parents.

Yoshi Touch & Go
In Yoshi Touch & Go, Baby Mario and Baby Luigi are carried by the stork; the stork gets hit by Kamek, which promptly drops both Baby Mario and Baby Luigi whenever a mode is selected in the title screen. In Score Attack mode, if the player hits over 300 points, Baby Luigi is seen riding the Stork at the end. In Time Attack mode, Baby Luigi is held captive by Kamek's Toadies. To rescue Baby Luigi, Yoshi must fling Yoshi Eggs at the Toadies carrying him. In Marathon mode, if the Yoshi gets defeated, Baby Luigi is seen riding the Stork, who flies to the area the Yoshi has been defeated. In the game's multiplayer mode, Vs. Battle mode, the second player's Yoshi totes Baby Luigi.

Yoshi's Island DS
Bowser and Kamek, in their quest searching for the seven star children, once again kidnap Baby Luigi, who is one of the kidnapped babies in Yoshi's Island DS. After Baby Mario, Baby Peach, Baby Wario, Baby Donkey Kong, and Baby Bowser team up, they all proceed to rescue him. Baby Luigi hides at the time Bowser and Kamek are checking the toddlers for stars, and, as a result, he never finds out that he is a star child himself.

Yoshi's New Island
Baby Luigi appears in Yoshi's New Island. In the game, he and Baby Mario are delivered to the wrong parents, setting the Stork off, continuing the search. Baby Luigi has been kidnapped by Kamek once again, but this time in Egg Island, so the Yoshis and Baby Mario go on an adventure to save him. After they save him, Baby Luigi and Baby Mario get delivered to the right parents.

Super Mario-kun
Baby Luigi has made several appearances in the Japanese manga, Super Mario-kun. He first appears in Volume 14, which is based on Super Mario World 2: Yoshi's Island. In this comic, the present Mario and Luigi travel to the past to stop Bowser from helping Kamek kidnap Baby Mario and Baby Luigi, and they also aid Yoshi to deliver the Baby Mario Bros. to their parents. As in the game, Kamek ambushes the stork and makes off with Baby Luigi, with Baby Mario dropping with Mario, Luigi, and Yoshi. As Baby Luigi arrives to the castle, Bowser does not appear to take a liking to Baby Luigi, despite Baby Luigi being playful, and ends up biting his head and even giving a spanking after Baby Luigi urinates on him. Later on, Bowser and Kamek torture Baby Luigi, and then Kamek disguises himself as Baby Luigi to throw the three heroes off.

Baby Luigi later appears in Volume 35, Volume 36, and Volume 37, which is based off Mario & Luigi: Partners in Time. A portion of volume 37 is featured in the English compilation of the series, Super Mario Manga Mania. His role in those volumes mirror that in the game it was based off of, with several key differences. In the beginning of Volume 36, Baby Luigi uses Baby Mario filled with water as a weapon and sprays Mario and Luigi with it. Baby Mario and Baby Luigi also use the Baby Drill as an attack rather than a method used to find beans: they attack Mrs. Thwomp and the adult Mario Bros. with the technique.

When the characters arrive at Star Hill, Baby Luigi builds a snowman. When the brothers go into peril with Commander Shroob, the snowman attempts to save them, but ultimately gets destroyed by Commander Shroob. Baby Luigi, thinking that he is useless, is then told by the snowman spirit that the flower on its head turned into an Ice Flower. Baby Luigi then uses an Ice Flower on Commander Shroob and the Support Shroobs, also unintentionally freezing his allies in the process.

Later in the comic, Baby Luigi teams up with Luigi against Mario and Baby Mario, after they were provoked by a Tanoomba masquerading as them. They both use shell armor, the Copy Flower, the Cannonballer, the Ice Flower, and the Fire Flower against Mario and Baby Mario, also while suffering their attacks as well. The four characters eventually find out that the Tanoomba tricked them and then teamed up to defeat the Tanoomba. The Tanoomba asks for forgiveness after the attack, and the four characters accepted it.

Baby Luigi appears only in the cover of Volume 40, which is a tribute to the series.

Club Nintendo
Baby Luigi appears in a Mario comic in the German magazine, Club Nintendo. As the the comic is based off Super Mario World 2: Yoshi's Island, he reprises the role of the hostage.

KC Deluxe
Baby Luigi makes an appearance in all three volumes of the Super Mario World 2: Yoshi's Island-based volumes (volumes 33, 34, and 35) of the KC Deluxe manga. While in the first and second mangas, he plays the same role as he did in Super Mario World 2: Yoshi's Island, he plays a more proactive role in the third volume, where, in original story arcs not based off the game, he adventures alongside Baby Mario and Yoshi, often supporting them such as piloting a Yoshi Helicopter to fix a broken railroad to help a passenger-filled train.

4-koma Gag Battle
In the Super Mario Daishuugou volume of the 4-koma Gag Battle released in 1996, one of the gags portrays a spin on the introduction of Super Mario World 2: Yoshi's Island. After Kamek steals Baby Luigi from the stork and Baby Mario dies when he hits the ground as a Yoshi fails to catch him, Baby Luigi is seen contemplating the future as the lead of the Mario series, thinking about Luigi 1, 2, and 3, Luigi World, Luigi Kart, and Luigi RPG. Kamek, who is disturbed by him, ends up tossing him out.

Dr. Mario-kun
Baby Luigi makes sporadic appearances in Comic Bom Bom's Dr. Mario-kun, sometimes being adult Luigi who transformed into him, other times having stand-alone appearances. In the May 2003 volume, adult Luigi and Wario first shrink, and then get turned into Baby Luigi and Tiny Wario respectively, with Tiny Wario bullying Baby Luigi. Dr. Mario fixes Baby Luigi and Tiny Wario by giving them a milk bottle, which turns him back into a regular-sized adult Luigi and Wario, though a the side effect generates viruses designed after Luigi and Wario. In this appearance, Baby Luigi is portrayed as wearing longer pants, gloves, and shoes designed after Luigi's. This was fixed in Baby Luigi's later appearances in the series.

In Episode 48 released in December 2006, loosely having elements based off Mario & Luigi: Partners in Time, the comic begins with Dr. Mario and Nurse Toadstool reminiscing the times Mario and Luigi were babies, still jumping around and defeating the Koopa Troop. They then notice Bowser Jr. and a red Virus strangely appearing in the pictures, who have traveled to the past to defeat Baby Mario and Baby Luigi. The story then cuts to the past, with Baby Mario defending Baby Luigi, where they fight back against Bowser Jr. and the red virus. After Bowser Jr. starts piloting a giant mech in the shape of Bowser's head, in the present, Dr. Mario, Nurse Toadstool, and Luigi meet up with a large Piranha Plant, who sends them back to the past to help Baby Mario and Baby Luigi defeat Bowser Jr. and the red virus; once they are both defeated, they start to face off against an evil timer.

The story arc continues in Episode 49, released in January 2007. After Dr. Mario fails to throw pills at the timer, the timer attacks and constricts Dr. Mario, which turns him into an 8-bit Mario. During the scene, Nurse Toadstool takes care of Baby Mario and Baby Luigi, holding them in her arms. After Baby Bowser and Bowser Jr. met each other, they escape on a Koopa Cruiser. Due to the evil timer earlier granting Luigi a large mustache, Luigi uses his mustache to fly the protagonists to the Koopa Cruiser. After the Piranha Plant downs the cruiser, the protagonists help 8 bit Mario out, with the combined power of Invincible adult Mario Bros. with the Baby Mario Bros. to defeat the timer. After the timer is defeated, the characters return to their respective time periods.

Mario Kart: Double Dash!!
Baby Luigi makes his playable debut in Mario Kart: Double Dash!!, his weight class being light-weight. Baby Luigi's default partner is Baby Mario and his kart is the Rattle Buggy. Their special item is a Chain Chomp, which can pull them forward at high speeds and knock over any opponent who gets in the way. Baby Mario and Baby Luigi also have a course in this game, which is Baby Park. Baby Mario and Baby Luigi are used as staff ghosts in both Baby Park and Sherbet Land; Baby Luigi is the dominant character of Sherbet Land. Also, file names in Mario Kart: Double Dash!! name the course Baby Mario and Baby Luigi (who are packed into one file), and the Baby Park staff ghost simply "BabyLuigi", even though Baby Mario is the dominant character of the pair.

Mario Kart Wii
Baby Luigi later returns to the Mario Kart series as an unlockable character in Mario Kart Wii as a small driver, meaning his karts generally have high acceleration, handling, drifting, and Mini-Turbo, but generally lower speed and weight. Baby Luigi's karts are the same as the other light-weight characters, except that his are green and share the same trademark L emblem as Luigi. Unlocking eight Expert Staff Ghost Data in Time Trials, winning 100 WFC Ghost Races, or playing 3,150 races unlocks Baby Luigi. He is tied with Baby Daisy for having the best speed bonus for small drivers, which makes any vehicle have a slightly higher top speed. Baby Luigi's biggest bonus is his weight bonus, and he is tied with Baby Mario in this category. Baby Luigi is used as a staff ghost in N64 Sherbet Land, making this the second consecutive time where Baby Luigi is the staff ghost for a course named "Sherbet Land".

Mario Kart 8 / Mario Kart 8 Deluxe
Baby Luigi returns as a playable racer in Mario Kart 8. Unlike Mario Kart Wii and like Baby Mario, Baby Luigi is a starter, like in Mario Kart: Double Dash!!, and his emblem is altered to differentiate his from Luigi's; the colors are reversed to make a white L in a green background. There are also bonnet frills around the insignia, a feature that was first introduced to Baby Mario and Baby Peach in Mario Tennis Open. As in all Mario Kart games he is playable in, he is a lightweight driver. His group specific stats, with the rest of the playable baby characters and Lemmy Koopa, heavily favor acceleration, handling, and grip at the cost of speed and weight, making him and the rest of the characters the lightest in the game. Nin★Massim's staff ghost uses Baby Luigi for Water Park. The Animal Crossing x Mario Kart 8 DLC pack returns Baby Mario and Baby Luigi's track, GCN Baby Park, where the starting banner is updated to 3D artwork of Baby Mario and Baby Luigi rather than the Yoshi's Island art style originally used. When the CPU uses Baby Luigi, he, alongside the other baby characters, occasionally uses the Biddybuggy body paired with Standard tires.

Mario Kart 8 Deluxe, a port of Mario Kart 8, returns all playable characters from Mario Kart 8, including Baby Luigi. Mario Kart 8 Deluxe has changed his stats, so he now shares stats with Baby Mario, Dry Bones, and small Miis. He has a higher top speed and weight stats than Baby Peach, Baby Daisy, Baby Rosalina, and Lemmy Koopa, as well as having equal or better acceleration than them, though he has lower handling, traction, and mini-turbo stats to compromise.

Mario Kart Tour
Baby Luigi appears as a playable character in Mario Kart Tour, available from the 2019 Halloween Tour. Baby Luigi is classified as a Normal character, and his special item is the Boomerang Flower. As of the Sydney Tour, Baby Luigi and Baby Daisy are the only babies without playable variants.

In pre-release material, including the beta test, Baby Luigi was a common character (early name of Normal) and his special item was the Boomerang Flower. His most preferred course was DS Luigi's Mansion in that he receives three items if he races on there. SNES Mario Circuit 1 was another preferred course though there he receives two items.

Mario Superstar Baseball
Baby Luigi appears in Mario Superstar Baseball as an unlockable speed character if the player completes Challenge Mode using Yoshi's team. Baby Luigi is classified as a speed character, which means he excels at stealing bases and maneuvering as an outfielder. Baby Luigi's special ability is Wall Jump, which enables him to rebound off walls to catch any would-be home-runs. Baby Luigi's worst stat is his batting, making it very difficult for him to launch balls far, and his fielding stat is low, which makes him make mistakes more often on the field and his thrown balls in the outfield travel slowly. In this game, Baby Luigi has positive chemistry with Baby Mario and Yoshi, referencing their roles in Super Mario World 2: Yoshi's Island, but negative chemistry with Boo, King Boo, and Shy Guy. Baby Luigi has six Star Missions in the game, and three of them involve taking advantage of his high speed stat: they require Baby Luigi to steal at least one base and dropping a squeeze bunt. His unique Star Mission is "Win Piranha Panic with no damage!", where Baby Luigi must score first in the Piranha Panic minigame without being hit by either Piranha Plant fireballs or other players' Bob-ombs.

Mario Super Sluggers
Baby Luigi appears in Mario Super Sluggers, where he is available from the start, unlike its precedent. He has better fielding skills than in Mario Superstar Baseball, while his running is still fast and his pitching remains average; as with other babies, Baby Luigi has poor stamina while pitching and tires out very quickly. Once again, his batting is among the worst in the game, and his special ability is Super Jump rather than Wall Jump. Super Jump enables Baby Luigi to jump higher than other characters who do not have this ability. In Challenge Mode, Baby Luigi is trapped by a bridge that was raised without warning by Bowser Jr. in Mario Stadium. In order to access the bridge, players first need to defeat the Magikoopa guarding the switch. Players can then rescue him in by flipping the lever of the switch in the proper direction to open up a bridge. The arrow directions to flipping the lever are inscribed on the sand on the beach nearby. After Baby Luigi is rescued, he points player characters towards the Mario Stadium, with Lakitu interpreting his incoherent baby onomatopoeia, saying that Baby Mario is trapped in there and he wants to rescue Baby Mario himself, thus joining the team.

Mario & Luigi: Partners in Time
Baby Luigi plays a starring role in Mario & Luigi: Partners in Time. Here, he teams up with Mario, Luigi, and Baby Mario to fight the Shroob invasion in the past. Most of the game, he travels piggyback on Luigi but ventures with Baby Mario if the adult brothers throw them. In battle, Baby Luigi battles identically to Baby Mario. His default ability is jumping on foes, which he cannot perform on spiked enemies. Baby Luigi, along Baby Mario, later acquire hammers to injure spiked foes and be able to venture further in the game. For all attacks, he must time the attack for the most damage. If not, Baby Luigi either does a hurt-like pose after a jump, drops the hammer head, or trips and lands on his face when using the hammer if the button is pressed too early. Baby Mario and Baby Luigi also acquire overworld abilities in the game: the Baby Drill, which enables them to dig underground; the Baby Spin, which allows them to reach hard to reach areas that Mario and Luigi cannot access, even with the Spin Jump; and the Baby Cakes, which enables them to slip underneath cracks that cannot be accessed by the Baby Drill and float on winds due to compressed weight. He can also use Bros. Items, but he needs a partner to do so. If Luigi faints, Baby Luigi drags Luigi out of battle and fights in his place; if Baby Luigi faints, Baby Mario or Mario carries him, and his added weight hinders dodging capabilities. If Baby Mario faints, Baby Luigi carries him when enemies are attacking, and it also hinders his jumping abilities. Stat-wise, he differs from Baby Mario in most ways. Baby Luigi has slightly less speed and less attack, but more HP and defense. However, he has more speed and less HP, defense, attack, and stache than his adult counterpart, Luigi.

Mario Sports Superstars
Baby Luigi is playable as a captain-type character in Mario Sports Superstars, where he makes his overall debut playing soccer, tennis and golf. Throughout the five sports, Baby Luigi's common type is his speed, with the exception of golf and tennis, which means that he is able to move around the field quickly as well as emphasizing on horse top speed in horse racing. In soccer, Baby Luigi trades power for speed and technique, meaning his shots are less powerful, but they are more accurate, and he can attack balls and maneuver around more easily. In baseball, Baby Luigi is a left-handed batter and a right-handed pitcher who is very poor at batting, but he excels at speed-related activities such as fielding and base-running and his pitching velocity stat is on par with his speed; in fact, if Baby Luigi becomes a superstar character in baseball, his pitching velocity becomes his best stat. When Baby Luigi is pitching, he has access to Fastballs, Screwballs, Sinkers, and Sliders, where, compared to Baby Mario, Baby Luigi trades the Curveball for a Sinker and a bigger Screwball zone comparable to Baby Mario's Slider zone. Baby Luigi's special move when he is pitching is a slider. In horse racing, Baby Luigi has very similar stats with his brother, Baby Mario; he has high horse top speed, high acceleration, with below average control and very low stamina, meaning that his horses are harder to control and they tire out more quickly and it takes longer for them to recover their stamina. Baby Luigi's horses have the highest speed stat in the game, being slightly higher than Baby Mario's, the second highest top speed, though Baby Mario has higher stamina than Baby Luigi to make up for the lower speed. In horse racing, the CPU Baby Luigi uses the brown default technical horse. In Pro difficulty, the CPU Baby Luigi equips his horse with the green Asian accessories.

Baby Luigi has a different type classification in tennis, where he is a Technical character rather than a speed-focused character, sharing this classification with Princess Peach. Technical characters such as Baby Luigi emphasize on ball control and accuracy, hitting to the edges of the court more easily. Baby Luigi has excellent volleying power, where he can smash balls at the net at quick speeds across the court. Baby Luigi's movement speed is on par with the other Speed classified characters. However, Baby Luigi's reach is very low due to his size, making it very difficult for him to hit lobs and balls out of his reach if his speed cannot cover it. Baby Luigi also has very low stroke abilities, so if he hits shots after they bounce, the ball will not travel quickly. Due to golf using different mechanics than the other four sports, Baby Luigi does not rely on speed. Baby Luigi's shots have a fade tendency to them, meaning that, assuming Baby Luigi is right-handed, his shots hit towards the left before curving to the right. Baby Luigi has a maximum drive of 187 meters, which is the lowest in the game. However, he makes up for those traits by having excellent sweet spot and control stats, meaning it is more difficult to whiff shots, especially in very penalizing terrain such as Roughs, and if he hits the ball outside the sweet spot meter, he will not receive a large accuracy penalty. Baby Luigi additionally hits balls very low, meaning that while it is more difficult for him to traverse higher elevations and hit over trees, his shots are less affected by the wind. When Baby Luigi is starred, his drive increases to 219 meters, with his sweet spot and control suffering only slightly, due to him having the lowest drive in the game.

As all playable characters, Baby Luigi receives five amiibo cards for each sport from the game's series of amiibo cards. Only his tennis and golf amiibo cards use artwork from past games; the rest of his amiibo cards receive original artwork. When players tap Baby Luigi's cards in, they receive 1-Up Mushroom-themed gear that Baby Luigi can optionally use, though the gear is only for aesthetics purposes. Players can also use 1-Up Mushroom gear for Baby Luigi if they have unlocked it through purchasing random-packed digital cards.

Dr. Mario World
Dr. Baby Luigi is a playable, downloadable doctor in Dr. Mario World, released on September 5, 2019, alongside Dr. Baby Mario, Dr. Baby Peach, and Dr. Baby Daisy. In this game, he wears a white lab coat with a green tie that displays the letter "L", the clothing being too big for him. Like the other babies, he is equipped with an item: in this case a medicinal container with his emblem inscribed on it. While Baby Luigi's regular variant carries a blue-colored bottle, his unused rare variant carries a red bottle. Dr. Baby Luigi's special skill changes objects into shells in both Stage and VS modes. In Vs mode, Dr. Baby Luigi is slightly slower than Dr. Baby Mario and faster than Dr. Baby Peach, but can send 2 rows of viruses to his opponent if his attack meter is filled. He also has a 60% chance of defending against 2-row opponent attacks with a 15% chance of defending against other attacks.

In Ver. 1.2.0 of the game, in Stage Mode, Dr. Baby Luigi is unlocked when players clear the Special Stage of World 7.

Other appearances
Although Baby Luigi does not receive a trophy of his own in Super Smash Bros. Melee, he is briefly mentioned in Baby Mario's trophy description. In Super Smash Bros. Brawl, he makes a relatively small cameo as a Sticker, depicting him, riding on Luigi, in the Mario & Luigi: Partners in Time artwork. He does not receive a trophy in Super Smash Bros. for Nintendo 3DS, but he has a small mention in the Yoshi's New Island trophy. He has a trophy in Super Smash Bros. for Wii U, however. Baby Luigi's trophy, alongside several other characters such as Shy Guy, is categorized under the Mario series as indicated by the Mushroom logo; however, he, with the aforementioned characters, is categorized under the Yoshi's Island series in the trophy box. In Super Smash Bros. Ultimate, while Baby Luigi does not have a stand-alone spirit, there are two spirits where he appears in them alongside Baby Mario, one being the Goo-Goo Buggy and the other being the Stork carrying them from Yoshi's New Island. The Goo-Goo Buggy spirit is unlocked from the challenge board when players KO three characters less than a minute in the match.

Baby Mario and Baby Luigi also make a cameo appearance in Mario Kart Arcade GP 2, with several notable characters. They are seen throughout Yoshi Park 1 and have a sponsor, Baby Land, seen in Mario Highway, Mario Beach, DK Jungle, and Bananan Ruins. In Yoshi Park 1 and Yoshi Park 2, they, alongside other characters, can be seen riding the swing ride.

Both Baby Mario and Baby Luigi can be seen in the crowd in the opening of Mario Power Tennis. They can be seen only in the first match where Mario and Luigi beat Wario and Waluigi.

Although Baby Luigi does not physically appear in Luigi's Mansion: Dark Moon, he is mentioned when King Boo mockingly remarks how he cannot tell the difference between him and the adult Luigi.

A full-color version of the Baby Luigi stamp from Mario Kart 8 makes an appearance as one of the collectible badges a player can earn in the Nintendo eShop free-to-start application, Nintendo Badge Arcade. He, alongside the other baby characters, appear in a Mario Kart-themed Badge Catcher.

Baby Luigi makes yet another cameo in Mario & Luigi: Paper Jam, where he appears on a Battle Card alongside his brother and their adult counterparts.

Baby Luigi, along with Baby Mario, Baby Peach, and Baby Daisy, has also received some merchandising. He is featured as one of the minifigures of the Super Mario Figure Collection as well as being featured as part of the Furuta Choco Egg series. Baby Luigi is also one of the many plushies manufactured by San-ei. He, alongside Baby Mario and Baby Peach, are also featured in character-themed styluses. A Baby Luigi plush is also part of the World of Nintendo line of Nintendo merchandise.

Physical description
Baby Luigi has a similar appearance to Baby Mario. Both have black, beady eyes, large head to body ratios, and a large nose. As of Mario Kart: Double Dash!!, Baby Luigi uses the same color scheme as his adult counterpart, except he wears green sneakers instead of brown work shoes and he lacks gloves. He also has brown hair covered by his trademark Luigi Cap. The only major difference between Baby Mario and Baby Luigi is that Baby Mario wears a red shirt and red cap, while he wears a green shirt and green cap. Several minor differences from Baby Mario include his head shape, his eyebrows, his waist, and his sideburns. Also, Baby Luigi's sneakers are green instead of cyan like Baby Mario's. In the Yoshi series, he is depicted wearing only a white diaper and his green cap.

In his appearances in the Super Mario-Kun, Baby Luigi has big round eyes instead of his usual black beady eyes to fit in the artstyle of the rest of the Mario cast. To differentiate between Baby Mario, due to the lack of color in the manga itself, Baby Luigi's shirt is colored white while Baby Mario's shirt is colored black, similar to their adult counterparts. Baby Luigi also has a full set of teeth in the Super Mario-Kun instead of having a single tooth as in the games.

Personality
Baby Luigi, as his adult counterpart, is described as being meek and cowardly. For the most part, Baby Luigi is friendly and optimistic too, as he gets along well with the other babies. Baby Luigi's timid nature is also evidenced in the Mario Kart Wii official guide, which states that he used to ride with Baby Daisy until her boisterous nature scared him away. Games such as Mario Kart: Double Dash!! and Mario Superstar Baseball also depict Baby Luigi as a shy person, stating that his appearance in Mario Kart: Double Dash!! is the first time he appears in front of a crowd. Baby Luigi also has an ability to sense danger; in Mario & Luigi: Partners in Time, he was the only one who knew that Cobalt Star's spirit was actually the imprisoned Elder Princess Shroob because he cried when he saw something in the Cobalt Star. He also hides from Bowser and Kamek as they attempt to locate the stars found in the star children. Although he is a crybaby, as seen in Mario & Luigi: Partners in Time, he seems to actually be a bit more braver than his older self.

In the Super Mario-Kun volumes that are adapted from Mario & Luigi: Partners in Time, Baby Luigi is portrayed as Baby Mario's cowardly, unwilling partner, and he often reacts to pressuring situations with shock and crying; the Super Mario-Kun also frequently replicates Luigi's reactions with Baby Luigi's and vice-versa, used as a comedic feature to highlight the similarities of the two characters. Often times, when confronted by the Shroobs, he immediately bows down and surrenders, usually to find himself attacked by them shortly afterward; this is a running gag with the Luigi characters in the three Mario & Luigi: Partners in Time volumes. He and Baby Mario are also able to speak articulately and in complete sentences. As with Baby Mario, he is shown to be very naive, and he and Baby Mario both undertake actions that can irritate their older selves. In volume 36 of the Super Mario-Kun, it is shown that Baby Luigi can be angered, to the point where it overtakes his normally passive reactions to stressful situations: he teams up with Baby Mario to use the Baby Drill as an attack against Mrs. Thwomp and the adult Mario Bros., he angrily pokes Baby Mario in the nose after a Tanoomba masquerading as Baby Mario pokes him in the nose, despite Baby Mario's confusion, and he was even about to furiously attack Commander Shroob after Commander Shroob destroyed his rebuilt snowman, much to Baby Mario's surprise.

Voice
Baby Luigi has been portrayed by Charles Martinet, who also portrays his adult counterpart, starting with Mario Kart: Double Dash!! and has been portrayed by only Martinet ever since. When he speaks, he usually sounds uneasy, just as Luigi. His voice is akin to a higher pitched version of Luigi, often oscillating to a higher pitch when he is excited or surprised, although there is a significant difference between Baby Luigi's voice and an edited Luigi voice clip. Apparently, Baby Luigi's voice is filtered to sound higher pitched. In Mario Kart 8, Baby Luigi is generally higher-pitched than in preceding installments.

Abilities
Baby Luigi has very similar abilities to Baby Mario, except with some slight differences. They are both always lightweight characters in the Mario Kart series, they are always speed characters in the Mario Baseball series, and both have rivaling speed stats in Mario & Luigi: Partners in Time, surpassing their adult counterparts' speed stats in the series. Baby Luigi, very much akin to his older self, however, is speedier than Baby Mario in most cases, often compromising power. In Mario & Luigi: Partners in Time, Baby Luigi is more defensively-oriented than Baby Mario, analogous to Luigi's stats compared to Mario. Baby Mario and Baby Luigi have a tendency towards Chain Chomps ever since it is portrayed as their special item in Mario Kart: Double Dash!!; they are able to use the Pocket Chomp, which is an item exclusive to Mario & Luigi: Partners in Time and combining the Baby Mario and Baby Luigi digital trading cards for a double play in Mario Super Sluggers unlocks a video titled, "Beware of the Chain Chomp".

Relationships
Baby Mario is Baby Luigi's older twin brother and best friend. Baby Mario and Yoshis often work together to save Baby Luigi from Kamek in the Yoshi's Island games and, according to the second cinematic from Super Mario World 2: Yoshi's Island, the bond between each other is strong enough to give Baby Mario the directions to rescue the captured Baby Luigi. In Mario & Luigi: Partners in Time, the brothers team up for the duration of the game and are often interacting with each other. The two have good chemistry in Mario Superstar Baseball and its sequel Mario Super Sluggers. In the Mario Super Sluggers challenge mode, Baby Luigi joins Mario and his adult self after informing them Baby Mario was locked in there by Bowser Jr.. Lakitu then interprets Baby Luigi saying, "Aw, he wants to rescue Baby Mario. Brotherly love is a beautiful thing!" Baby Mario is also Baby Luigi's default partner in Mario Kart: Double Dash!! and the two go with each other to Mario and Luigi's tennis match in Mario Power Tennis. They share a course in Mario Kart: Double Dash!! and are portrayed together in Mario Kart Arcade GP 2. Baby Luigi's site bio for Mario Kart Wii, however, heavily implies that he has a sibling rivalry with Baby Mario, mirroring their adult selves' sibling rivalry. Baby Luigi has good relationships with other babies, namely Baby Daisy, In Mario Kart Wii, there is a statue of the two holding hands and dancing together on the Daisy Circuit course. The official guide for Mario Kart Wii also states that Baby Daisy used to ride with him until he got frightened of her rambunctious personality. In the first fight for the Baby Mario Bros. in Mario & Luigi: Partners in Time, Baby Luigi is seen playing with Baby Peach, calming her down, while Baby Mario fights Baby Bowser. Baby Luigi and Luigi have also positive interactions with each other in Mario & Luigi: Partners in Time, although Luigi is very forgetful, such as times when he leaves Baby Luigi behind during Petey Piranha's arrival. He is very caring for Baby Luigi and usually calms him down when he is crying. A scene on Yoshi's Island in Mario & Luigi: Partners in Time involves Luigi about to eat a cookie but he realizes Baby Luigi wants it. He decides to give the cookie to Baby Luigi, and Baby Luigi thanks him afterwards. At the end of the game, Baby Luigi is very reluctant to go back to the past and leave Luigi behind. When Baby Luigi finally decides to give in, he sends his hammer as a gift, but humorously bonks Luigi on the head instead of simply giving it to him, as Baby Mario does to Mario.

Official profiles and statistics
Baby Luigi has been classified as a lightweight and speedy character in every game he is playable in. Bios typically highlight Baby Luigi's timid nature and his hostage role in the Yoshi Island series; he is often compared to his adult self. As Baby Mario, some of his bios lampshade the fact that he and his adult self are playable alongside each other in the same game.

Quotes

 * "Checkered blankie for Luigi! Woo-hoo!" – Mario Kart: Double Dash!!
 * "Uh-oh, Baby Luigi time!" – Mario Kart: Double Dash!!
 * "Baby Luigi number not one." – Mario Kart: Double Dash!!
 * "Thank you very much!" – Mario Kart: Double Dash!!
 * "Baby power! Baby power!" – Mario Kart: Double Dash!!
 * "Way nice! Way nice!" – Mario Kart: Double Dash!!
 * "Oh boy! Oh boy!" – Mario Kart: Double Dash!!
 * "Haha, Luigi, Luigi, Luigi number one!" – Mario Kart: Double Dash!!
 * "Baby Luigi!" – Mario Kart Wii
 * "Vroom vroom! Hehe." – Mario Kart Wii
 * "He-he-he-he!" – Mario Kart Wii
 * "Okey dokey!" – Mario Kart Wii
 * "Let's-a go!" – Mario Kart Wii
 * "Baby on the Blue Team!" – Mario Kart Wii
 * "Go Red Team!" – Mario Kart Wii
 * "Oh yeah, Baby Luigi!! Yeeaaahhooo!" – Mario Kart Wii
 * "Yeah! Baby Luigi almost win!" – Mario Kart Wii
 * "Ohhh, I don't win." – Mario Kart Wii
 * "Mama!" – Mario Kart: Double Dash!!, Mario & Luigi: Partners in Time
 * "Mario!" – Mario & Luigi: Partners in Time
 * "Go Luigi! Go Luigi!" – Mario Kart 8
 * 「おまえらよくもー!!」 ("You're next!") -Super Mario-Kun, volume 36, page 81
 * 「やっぱり,ボクじゃダメだ.... 」 ("I'm useless after all...") - Super Mario-Kun, volume 36, page 81
 * 「ねーねー. ボクすごいでしょー!!」 ("Hey hey. I'm amazing!") - Super Mario-Kun, volume 36, page 83
 * 「うーあと5分ねかせてー. 」 ("Uhh, let me sleep another 5 minutes.") -Super Mario-Kun, volume 36, page 102