The third game in the Mario & LuigiRPG series, released in 2009 for the Nintendo DS. Its Japanese name is Mario and Luigi RPG 3!!!.A mysterious disease, the Blorbs, are causing Toads to swell into giant balloons. In a bid to capture Princess Peach and use her to claim the dark power of the Dark Star, an Artifact of Doom that is buried beneath the Mushroom Kingdom, Fawful tricks Bowser into eating a mushroom that lets him suck up her, the Mario Bros., and most of the Toads in Peach's Castle.With Peach, Mario and Luigi trapped inside Bowser's body, Fawful takes over Bowser Castle, capturing some of his minions and brainwashing the rest. Bowser embarks on a journey to take back his palace and free all his minions. Meanwhile, Mario and Luigi aid him from inside his body when necessary in the midst of collecting the three Star Cures needed to counteract the Dark Star.One of the quirks of the game is that Bowser can't be controlled unless Mario and Luigi are inside his body. That's because of the new mechanic of the Vacuum Block, which allows Bowser to suck up smaller enemies or, less frequently, parts of the enemies that temporarily raise Bowser's stats. When Bowser is ingesting entire enemies, the screen cuts away to a battle inside Bowser between the Bros. and the enemy. After this battle is over, the outer battle resumes (unless Bowser ate the last enemy). Notably, this is the only way that Mario, Luigi, and Bowser can fight against common enemies in the same battle. Another feature is that while most of the world is the same format as the previous two games, a top-down view of the world, all the stages inside Bowser's body are 2-D, side-scrolling levels.
Luigi gets his moment to shine during a few plot points.
The game is as much a Bowser game as a Super Mario game.
Airborne Mook: Some enemies can fly or float, and are thus immune to hammers, shells, shockwaves or any other low-hitting attacks. Bowser himself is unable to hit them via normal attacks as they either fly too high or can easily dodge his slow attacks. But he can still suck them up...
Alien Geometries: There are pipes inside of Bowser that got there when he sucked them up. They lead to the outside of Bowser's body, without, at any point, going through Bowser. And in doing so, also raise the Bros.' size from microscopic to macroscopic. This sort of thing is par for the course in Mario World, though. Why do you think they're called warp pipes?
Unusually for a game that bases its battle system on dodging attacks, Peach's Castle has one; it's even called "Unavoidable attack". Bowser will take damage from this and cannot counter it.
The Stone Blooper (whom you fight inside Bowser) has an attack where it embeds itself into the ground and drills into it, causing Bowser damage. It's one of the very few attacks by a normal enemy you cannot prevent.
Amazing Technicolor Battlefield: Bowser even compliments the final boss on creating the "perfect backdrop for an awesome final battle." Said quote is actually the page quote for that page.
Angry Guard Dog: Broggy, Broque Monsieur's guard dog. He's pretty much pissed off at everything and can be unlocked as Bowser's final Special Attack. It also seems to have adopted his master's hatred of Mario since he'll growl if he comes too close.
Apathetic Citizens: Averted in the case of the Dimble Wood Wigglers. After Bowser ransacked the farm and the forest became a battlefield for Giant Bowser and his castle, they increased their security measures.
Arson, Murder, and Jaywalking: Wiggler accuses Bowser of invading and contaminating his farm, pulling out his giga-carrot, and eating it. Even though he made you do the last part.
Bag of Sharing: Both the Bros and Bowser share coins and items. Makes one wonder where the coins gets stored. Also, when either characters are selling things in shops, the fact that Mario can sell a huge turtle shell and spicy drumsticks and that Bowser can sell mushrooms and overalls is a bit odd.
Bag of Spilling: Averted in one case where the brothers decide to use a move ("Hit Mario with a hammer to make him small") from the first game when it is required, but otherwise played straight.
Balloon Belly: Lots. It's part of Fawful's plan to extract Princess Peach from Bowser's body after tricking him into trapping her in there — later in the game, Bowser can go back and get fat again whenever he wants (allowing Mario and Luigi to gain access to Flab Zone again, but there is no need to). The Bros. use it to their advantage as part of their "Snack Basket" special, using a giant Luigi to make a quake that damages all enemies, as well as to inflate Mario with air or water for travel purposes. And of course a bunch of Toads coming down with the Blorbs. When it gets cured, one Toad seems to stay sick, until he says that it's how he normally looks like.
Beam-O-War: A brief fire breathing contest between Bowser and Dark Bowser.
Blah Blah Blah: Bowser absolutely hates being made to listen to long-winded speeches, at one point even shouting, "TOO MANY WORDS."
Bonus Boss: There are three Shroobs locked up in Bowser's Castle that give you a Bros move for winning. There's also the Challenge Node in Bowser's body (somewhere around his...liver?), although the fights there are only upgraded versions of old bosses. And are short, so short that there is a limit to how many moves you can finish them off in. This culminates in a Boss Rush incidentally featuring its own Bonus Boss: Bowser X.
Boss Bonanza: The repurposed Peach's Castle holds Junker, Blizzard Midbus, Dark Star, Super Peach's Castle, Dark Fawful, and Dark Bowser and the Dark Star Core. Starting with the Dark Star, the only plot events are these boss fights and the buildup for them, and if you just go right for these bosses and do nothing else, there won't even be any regular enemies.
Boss Remix: Bowser's Theme is remixed for the Giant Boss Battles.
Boss Rush: Class 7 in the Gauntlet. Plotwise, the last four bosses: the Dark Star, Super Peach's Castle, Dark Fawful and the Vaccuum Helmet, and Dark Bowser and the Dark Star Core. Although you can do whatever you want in between, plotwise, only things related to the fights happen in between, like the final Rump Command minigame to activate the Super Peach's Castle fight and a minigame fight with Dark Bowser.
Bread and Circuses: Fawful. Not only does he win over the respect of nearly all of Bowser's henchmen, but he turns Bowser's Castle into a theater. And even Bowser has to admit that his cooking is excellent.
Breath Weapon: Bowser, whose arsenal includes his trademark fire breath.
Chest Monster: Trashure (and Dark Trashure, later in Peach's Castle), a fairly regular enemy that doesn't bother trying to trick you. The chest opens at low health, giving Bowser the chance to inhale the coins inside. The regular attack also sometimes spits out coins (or mushrooms). It's also a bit of a Metal Slime however, tending to flee the battle.
Climax Boss: Alpha/Beta Kretin, filling the same role as Petey Piranha in the previous game, but with a much larger plot revelation afterwards.
Cognizant Limbs: Dark Fawful's three legs have to be destroyed (and you have to get rid of his two eyes as well so he won't hide those legs before you attack) before the Brothers can hit his true target, the Dark Star Core.
Collection Sidequest: Finding the Blitties, which lets Bowser use Broggy in a Special Attack. Beans also return but boost stats straight away. There's also collecting the various Attack Pieces that aren't necessarily needed to finish the game and are SP expensive, but a couple of them can become Game Breakers.
Isn't this whole game basically a Continuity Nod? Think about it: In game 1 Fawful is the dragon to the Big Bad Cackletta/Bowletta. In game 2 he sells badges to Baby Mario and Baby Luigi claiming that one day he will have his revenge. What does he do in this game? That's right. He gets his revenge and becomes the Big Bad.
"But... Now that I am thinking... Cackletta's [sic] revival was all thanks to my quite nasty efforts! Which means, all this time... I am Fawful, who is just a toady! Such working, all for others!" - from Superstar Saga
Though probably not intentional, the last battle of the first game is you fighting an evil spirit inside Bowser, the final battle of this game is you fighting an evil spirit inside Bowser.
Cool Castle: Bowser's Castle and Peach's Castle. They're both ridiculously massive in size and amount of rooms (four or five floors each minimum), but they actually become giant robots. The former can fly to dodge missiles and fight against Bowser himself, the latter becomes a massive robot which attacks via laser beams and black holes. Note that neither of them normally do this, but Fawful tinkered with them.
Cool Train: The battle between giant Bowser and a train nicking stuff from his vault.
Cranial Processing Unit: The Mechawfuls definitely have whatever controls them inside their heads, to the point that the head specifically has to be destroyed separately to stop it from regenerating the body.
Creative Closing Credits: After the boss battle, Bowser is furious to find out that Mario, Luigi and Starlow's been in his body the whole time, and picks up a fight. Cue the closing credits, where he gets KO'd as usual, and a "Where Are They Now?" Epilogue showing what happens next. Oh, and after that, a heartwarming scene where Bowser gets a cake from Peach.
Cultural Translation: In most versions of the game, Broque Monsieur is stereotypically French (Even in the French Canadian one, where he's France French, with the associated language differences and stereotypes.). In the France French translation, he's a stereotypical English gentleman. He speaks Gratuitous English in the Japanese version too. For example, one of his lines is "Oh my dog! What's happen!".
Cute Kitten: Blitties. Collect them all and you'll get Broggy as a minion. Do Broggy's attack perfectly, and all 15 of them will join him in tackling the enemy.
Deadpan Snarker: Bowser and Starlow have moments of this, mainly toward each other.
Decoy Protagonist: While Mario and Luigi are the ones to gather the Plot Coupons, the game is arguably more Bowser's story. Well, the name "Bowser's Inside Story" isn't Just for Pun...
Death of a Thousand Cuts: The Magic Window uses a ludicrous amount of your SP and the individual attacks only do a quarter of the damage your normal jumps can do... but it will not stop until either you screw up an Action Command or everything on the other end of the field is dead.
Demonic Possession: Notably averted in this game. The final boss does not possess any of the characters, and certainly not Bowser. He does, however, fight in a form similar to that of Bowser, and part of the final boss does have Fawful's Dark Star form being fought inside Bowser by Mario and Luigi.
Determinator: Shown through one of Dark Bowser's attacks in which Bowser has to face an onslaught of dark versions of his minions. It's pretty danged awesome to watch Bowser simply swat every single dark minion aside as he tromps toward Dark Bowser.
Deuteragonist: In two layers, no less. One layer is Bowser as one protagonist and Mario & Luigi as the other protagonist (since they are always together cooperatively). And, of course, Mario and Luigi are of equal mutual importance as a protagonist team.
Disc One Nuke: The Koopa Corps for Bowser, which also remains useful for the rest of the game. Works on both multiple and single targets efficiently, and when done correctly its damage output exceeds several of the more expensive late-game attacks, such as the Magikoopa Mob.
Dragon Ascendant: Fawful, although he does not explicitly reference the events in the first game.
Easily Forgiven: Bowser decides to release Private Goomp, Sergeant Guy and Corporal Paraplonk for betraying him for Fawful as long as they help fix the castle. They wereBrainwashed though, so he can't exactly hold a grudge. Bowser does care for his minions, after a fashion.
Evil Is Not a Toy: Subverted. The Dark Star overpowers Fawful to regain the energy he had absorbed from it, consuming Fawful along with it. However, the two seem to form a mutually beneficial relationship, with Fawful powering up Dark Bowser from within during its fight with the real Bowser, and the Dark Star's core lending its energy and assistance to Fawful in his own battle against Mario and Luigi.
Exposition Fairy: Starlow, a.k.a. 'Chippy', who tries to assist/annoy Bowser. He is not amused when he finds out 'Chippy's' identity.
Face-Heel Turn: Private Goomp, Sergeant Guy and Corporal Paraplonk were bribed over to Fawful's side and they lock Bowser in his own safe. Bowser forgives them, though.
Fake Ultimate Mook: When Mario and Luigi finally get to the first areas Bowser visited, the "large" enemies are jokes, but the small enemies that Bowser instantly defeated without battle are level appropriate.
"Fantastic Voyage" Plot: Kind of the point of half the game. Even after gaining a way to get outside of Bowser, Mario and Luigi aren't free from this trope; Mario and Luigi enter into a giant Sockop (Shoe-like pitcher plants) at one point in Dimble Woods, called Kuribo appropriately enough.
Final Exam Boss: Bowser X counters every Bros. Attack used by inhaling it, making you unable to access that technique until six turns afterwards. This practically requires you to master each of the ten Bros. Attacks in order to defeat him.
Fixed Encounters: Best of all, you can get a free strike on enemies by jumping on them (as Mario and Luigi) or punching/burning them (as Bowser) in the overworld.
For The Chortulz: While Fawful does have a plan, very few of his projects involve it at all. The only apparent motive for 80% of his actions appear to be for sheer fun.
Flanderization: A subtle example. Fawful's speech patterns are somewhat MORE broken than in Superstar Saga, where he would simply talk in first release Final Fantasy I level sentences with some Zero Wing thrown in near the end. Here, he's more prone to Zero Wing level sentences, with the new Redundancy Department deskboy being Midbus (whom Fawful likely taught how to talk like himself.)
At one point in the game, the bros have a boss fight against Bowser. In the fight, Bowser will more than likely have no stats in common with the ones he had while being controlled by the player, having far more HP than he would have by that point as well as lower power and defense. In addition, none of the gear he may have had on will be in effect, and he'll never use items or do more than an "Ok" with his special attacks.
The Goomba: Goombules for Mario and Luigi, Chuboombas for Bowser. Both of which are based off Goombas, of course. Bowser can summon his own original Goomba for his first special attack.
Goomba Stomp: Enemies try to do it to Bowser in Bowser's Inside Story. Luckily, he can duck under his spiked shell.
Gratuitous English: Broque Monsieur (Brirock in the original) in the Japanese version as well as the French version.
Gratuitous French: Broque Monsieur and Broque Madame. Broque Madame even tries to take this into Everything Sounds Sexier in French. In Canada, the French localisation set "Mosieur DuBloc" as an authentic French of France, with all the stereotypes and language differences.
Guide Dang It: The requirement for getting a perfect 100-point score from the puzzle minigame, made even worse by the fact that few people know about this. No matter how well you do on an individual puzzle, you will only get up to 99 points. The trick is that it's an event triggered by clearing all five puzzles in less than 2 minutes. Considering the usual scores are for individual puzzles, this isn't exactly intuitive.
Here We Go Again: After everybody gets out of Bowser's body, Bowser becomes enraged at finding out what happened and yet again starts fighting with the Mario Bros. Cue the credits.
Honest Axe: When Luigi is rescued from sinking by Princess Lipid, she asks Mario if he dropped him or a "treasure of everlasting wonder". You don't actually get to choose: she automatically assumes Mario wants the treasure even though that's not the case.
One of Bowser X's attacks starts off with a simple fireball attack. Upon one of the Bros. hitting it back with a hammer, it sets Bowser on fire, causing him to rain flames on the Bros, then follow it up with a spiked shell ball slam.
Bowser does it during a minigame in Peach's castle where a giant piranha plant sets his rolled-up shell on fire. He uses it to his advantage and rams the piranha plants to death. Later, Bowser and Dark Bowser set each other on fire, and both of them roll up into flaming spikeballs trying to tackle each other.
Infinity–1 Sword: A-OK Wear raises all stats by a good amount and prevents all Status Effects. While you can only get it once you have the Star Rank and it costs a whopping 20,000 coins for one pair, it's possible to earn that much money by having Mario and Luigi go out and explore all the areas that Bowser explored at the beginning (As soon as Bowser rescues the Koopa Troopas). It makes the last two dungeons and the Gauntlet a lot easier.
Informed Ability: Bowser apparently knows how to give professional massages. He just doesn't want to, unless there's compelling compensation. Given that he's probably gotten massages from his minions a lot, it's likely he picked up some techniques from them.
Insistent Terminology: Double Subverted with the Miracle Toadley Cure. At first, he insists Starlow refer to the Miracle Cure by its full name, but then he seems to have dropped the issue soon after. Yet if you talk to him later, he's muttering the full name under his breath.
Intentional Engrish for Funny: Fawful has passed down his speaking style to his dragon, Midbus. However, it's nowhere near as bad, and he simply speaks in a somewhat redundant fashion like the badly translated/dubbed kung-fu movies.
Just Eat Him: The game would have been very short if Bowser had chewed.
Lady Looks Like a Dude: It's easy to think Starlow is male, when she's actually quite female. The only in-game hint to her gender is a set of feminine eyelashes on her character art...which you only see after you beat the final boss.
Laser-Guided Karma: Bowser's entire history with the second Star Cure. Before the events of the game, Bowser entered the house of a sage named Kuzzle, who greeted him amicably and challenged him to solve a jigsaw puzzle. Bowser couldn't figure it out, and in a rage attacked him, trashed the place and stole his Star Cure. But having no use for it, he put it away in a safe in his castle. Cut to the game's events, and in his efforts to reclaim the Star Cure in a time of need, he gets betrayed by two groups of people he had previously treated well, is severely injured by one of them, is forced to solve a jigsaw puzzle to remember the safe's combination, and is finally locked within the safe himself.
Low Level Run: Finishing the game with Mario at Level 17 or lower will give you a message admiring your dedication. Though it has been confirmed by a few players, this is often regarded as an Urban Legend of Zelda by many, which is not helped by most FAQ's claiming that the message can be received with Mario or Luigi under Level 17.
The final boss battle of the game is Bowser versus the Dark Star turned into Dark Bowser, a clone of him. One of its attacks is to punch him, which must be countered by Bowser's own punch, followed by a shell slam, which must be countered by Bowser's Shell Shield. He also uses Bowser's various abilities, such as fire breath, and even (when giant) mimics a Bowser Army attack.
Bowser Memory M and Bowser Memory L are a particularly bizarre example.
There's a segment where Luigi gets stuck from the waist down inside a Sockop, a monster that looks like a green boot, in what is almost certainly a reference to the "Kuribo's Shoe" from Super Mario Bros. 3. It even lets him walk safely over thorns and other hazards like the Kuribo's Shoe. And just in case it wasn't clear, you later see a Sockop named Kuribo.
This is a bit of a stretch, but during the Boss Battle with Junker, a bucket falls onto one of the Bros.'s heads and you (the player) must guide them around, avoiding being crushed by Thwomps. This is very similar to the premise of the Japan-onlyMario & Wario, where the fairy Wanda must successfully guide Mario through a level, while one of various items is obscuring his vision. One of said items is a bucket.
Nice Hat: Fawful's rocket hat after he powers up, which the Brothers have to destroy before Bowser can actually fight Fawful, lest the hat continually regenerate his health far faster than Bowser can take it down.
No Fame, No Wealth, No Service: The heroes can't enter two high-class shops in the Mushroom Mall until they've proved that they're the right sort of clientele... even though most inhabitants of the Mushroom Kingdom recognize Mario on sight.
Accidentally setting off an entire storeroom of Bob-ombs does nothing more than send Bowser across the world map.
Fawful blows himself up at the end of the game, which not only doesn't harm Mario, Luigi or Starlow in the slightest, but propels everyone out of Bowser's body and only gives Bowser himself a spicy taste.
Ocular Gushers: Luigi does gushers of joy when Mario saves him in Bowser's body, and the Chuboombas do this when Bowser eats their lollipops.
Oh Crap: The usual reaction to Giant Bowser, from the Monty Moles seeing him tower above their train with a train to the entire Toad Town screaming in horror.
One-Hit-Point Wonder: The Daredevil Boots turn either Mario or Luigi into one of these, doubling their attack power but causing them to go down in one hit regardless of their health.
One-Man Army: Holy heaven and hell, Bowser. He literally has to fight through an army of a couple dozen mooks assaulting him just to make it to the Final Boss—and this is merely one of said boss's attacks!
Dark Fawful/Dark Star Core can turn into a multi-limbed monstrosity.
Pretty much every later boss in the game as well as the giant bosses.
Only Known by Their Nickname: Starlow's name is mentioned all of once in the prologue, once in the ending, and once almost exactly halfway between. One can be forgiven for thinking of her throughout the entire rest of the game as "Chippy" — all of the good guys know her real name, but two are silent protagonists, and Peach spends most of the game captured or sitting in town.
Outside-the-Box Tactic: Some regular enemies can be defeated instantly by a specific move, like Bowser's firebreath on Bob-Ombs (trapped in Jailgoons). However, some will just cause the enemies to retreat, thus netting no XP from them.
Palmtree Panic: Plack Beach, which has an odd tooth decay theme. It's actually called "Tooth Decay Beach" note Musshība Beach in the Japanese version, doing away with the pun entirely.
Plot Tunnel: Some times, Bowser will refuse to go anywhere (or is incapacitated), forcing you to use the Bros, even though you'd like the opportunity to just go back to Dimble Wood and give Broque Monsieur those damn Blitties.
Fawful: "A nuisance barge barging in at a critical time for us!" Bowser: "Nuisance barge? GWAHAHA! Buddy, you're like a nuisance SUPERTANKER!"
Puppeteer Parasite: Chain Chawfuls are Chain Chomps brainwashed by a Fawfulized parasitic worm in their head. Bowser can inhale the parasite to kill it, which frees the Chain Chomp from the mind control. But you don't get EXP.
Puzzle Boss: Several bosses need a very particular strategy (such as one specific brother attacking an appropriate weak point, or using the boss's flunkiesagainst him) to defeat.
Ring Out Boss: The Tower of Yikk, Bowser's second giant opponent. Made easier by how easy it is to stop him from escaping the water afterwards.
Peach's castle, when it creates a second black hole. You'll need to punch it into the black hole behind it and avoid getting knocked into the one behind yourself (It'll use an Always Accurate Attack to knock Bowser in anyway).
Robo Speak: The mechanised form of Princess Peach's Castle that's Bowser's final giant battle foe. ACTIVATE BLACK HOLE ENDGAME!
Royals Who Actually Do Something: Bowser. In fact, as much of a Dumb Muscle he may be, he seems to be the only one who does something useful in the Koopa Kingdom. Any other Bowser Baddie with a shred of competence ends up betraying him for Fawful. Lampshaded, where Bowser angrily shouts to his Goombas trapped in cages that while they're busy playing "Cram in the Cage", he gets things done!
The Runt at the End: One of the Blitties in a perfectly-executed Broggy Bonker and one of the Goombas in the Fawful Theater.
Scooby-Dooby Doors: The Magic Window attack. The bros hop into a disappearing, reappearing window and continually hop out onto enemies in random order until you miss a hit; either Mario, Luigi, or both at the same time. The frequency of the hops speeds up as you continue to get it right, and when it really gets going, you can actually see multiple copies of the same bro onscreen at once.
Seeker White Blood Cells: One room inside Bowser features a large worm boss that is eating what appear to be white knights. After you defeat the worm, the knights ambush you and send you falling. It's not explicitly stated that these are white blood cells, but Toadbert's description of their intent matches perfectly.
There's also Alpha Kretin, who is by no means a white blood cell, but attacks in the same way, swarming Princess Peach and then taking some kind of monster form after it's spun away by Mario and Luigi. Sadly, it also appears in the Gauntlet.
Segmented Serpent: Wiggler is fought like this. Like most examples, the head is the weak spot. Unlike most examples, you want to target his body segments first, as its head is immune to damage until you turn all of the body segments yellow (by damaging them).
Self-Imposed Challenge: If you get a high enough score in the Green Shell mini-game, you will recive an accessory called the Challenge Medal. This makes all of the enemies in the game a score tougher, but nets you extra Gold, effectivley putting the game on hard mode.
Sequence Breaking: Generally very hard to pull off, but after the first Star Cure, you can get six of the needed Attack Pieces in Dimble Woods before you should. You still can't get past the Wiggler though.
Shadow of Impending Doom: Happens three times to Bowser, by his own castle, then by the Tower of Yikk, then by Peach's Castle. The second time, he even tries to recall what happened, but gets squashed before finding out. As for the third time, Bowser had no time to react before it squashed him.
Bowser: "Weird! It got dark! I feel like this sort of thing happened before... And then..." *Stomped*
The English localization seems to feature references to internet memes. Fawful's first line of dialogue in the game is "A Winner is you!" and after the boss fight at the Toad Town clinic, Bowser uses the phrase "Cry Moar". (Though he spells it more.)
There may also be the enemy named Fawfulcopter. However, they don't go "Soi soi soi"
Midbus's final form seems to resemble Ganon. Also, that logo on his shoulder looks suspiciously similar to the Pigmask logo in MOTHER 3...
Remember the Boo and the Koopa who are referred to as "Honey" (the female) and "Darling" (the male)? Doesn't that sound a littlefamiliar?
Fawful sings a song reminiscent of the Scooby-Doo theme in one scene.
Private Goomp, Sergeant Guy and Corporal Paraplonk each share the same rank and coloration as three characters from Sgt. Frog.
Shut Up, Hannibal!: As can be expected of him, Bowser has very little patience for pre-battle taunts and banter when he's being controlled by you.
Bowser: Bah! You like compost? I'll compost your FACE!
Smurfing: The Emoglobins have a habit globin of replacing globining a word or two with "globin." Some players globins don't like this feature globin, but they don't underglobin-stand. IS THAT NOT GLOBIN?!
Slasher Smile: Fawful. Even creepier when he gives a real chortle. Doubly so when he tries to take out Mario and Luigi as he dies
Because nothing portrays the quest of a giant angry turtle like cheerful, upbeat background music. Especially Bumpsy Plains / Blubble Lake.
EVERY BOSS except for the final boss and giant bosses has the same cheery, light-hearted boss music, even Alpha/Beta Kretin, who just kidnapped Peach, the fight between the Bros. and Bowser, the Dark Star, and Dark Fawful, both of which are part of the Boss Rush (though one in plot only) at the very end of the game.
Spikeballs Of Doom: Bowser becomes one during his Shy Guy Sling move, as well as when he gets the ability to roll around out of battle.
Spikes of Villainy: Subverted; Bowser's Horn stat has the same function the Bros' Stache stat does.
The Spiny: Certain enemies have spikes on their back or are on fire, jumping on these will make Mario or Luigi take damage.
Broque Monsieur and Broggy. Say "block monster" and "blocky" with a heavy French accent. "Broque Monsieur" and "Broque Madame" are also puns on "croque-monsieur" and "croque-madame", types of French grilled sandwiches.
If the Monty Bros. didn't come out of the Fawful Express to bomb Bowser, they would have had a much better chance of escaping and winningnote Countering the bomb attack does HUGE damage to the Fawful Express, even more than an 'Excellent' fire breath.
Dark Star's summoning of Dark Satellmites. Hitting a Dark Satellmite back into it will make it vulnerable.
Dark Bowser growing via help of the Dark Fawful Bug. Thanks to this, Bowser is able to punch Dark Bowser's stomach and force him to cough up the Dark Fawful Bug.
Taken for Granite: Subverted by Chakron, who has stood in one position so long his muscles have locked like that. Also subverted in that he's happy like that, and actually becomes upset when you break him out of it.
The things the Fawful Express Mole crew say before/during the battle with Giant Bowser are exactly the most idiotic things possible, including their entire plan via villain monologue and their weakness.
Fawful at the beginning, giving Bowser an unintentional tutorial when watching him fight Midbus.
Bowser, before entering his vault: "This is one place that stupid Fawful NEVER could break into!". Then he goes in and sees the train tracks...
Theme Naming: Fawfulized enemies will have part of their name replaced with part of Fawful's name (Crocodile-Crawful, Chain Chomp-Chain Chawful, Monty Mole-Mawful Mole, etc)
The Mole: Literally and played straight. The Monty Mole Brothers reveal themselves to have been working with Fawful all along, right before running Bowser over with the Fawful Express.
Throw the Dog a Bone: In the ending, Bowser, after helping to put an end to Fawful, destroy the Dark Star, and find a cure for the blorbs; challenges Mario and Luigi to a fight and yet again gets the hell beaten out of him during the credits. However, as he is nursing his wounds at his castle, he receives a thank-you cake from Peach and the Mario Bros.
Tiered by Name: All of the bosses from the Challenge Node are bosses from the main story made more powerful. They all have the same name as the original bosses but with "X" at the end of their names. Even the bonus boss Bowser X.
Time-Limit Boss: You only have a set number of turns to defeat the Fawful Express, otherwise the road ends in an unstable bridge and Giant Bowser will fall as an instant Game Over.
You also have a turn limit when fighting the Challenge Node bosses.
Toilet Humor: Wisdurm farts in Luigi's face. Possibly also Truth in Television, as some types of insects in real life actually do expel gas from their abdomen to deter predators.
Bowser has quite a few moments of questionable rationale. He wouldn't be Bowser if he didn't, though. For instance, he gorges himself on an entire kitchen's worth of food, and then deciding to work it all off in a single gym pass. The player can repeat this as many times as they want.
Every single Toad suffering from the Blorbs reports having been offered a Blorb Mushroom by a mysterious stranger, and then eating it. They are literally eating strange mushrooms with the same name as the disease it causes.
Bowser (with the help of Mario and Luigi, of course, but still a welcome relief from the severe case of Villain Decay).
Not to mention those Shroobs in Bowser's Castle. Just take a look at their stats before and after.
Fawful goes from the second-in-command Dragon, downgraded to a shop owner, and suddenly is the primary boss of the game? In fact, one could argue he made an even better villain than his old mentor Cackletta...
Training Boss: Bowser, who is the first boss for the Mario Bros.. Midbus, who is Bowser's first boss. After that, Broque Monsieur who teaches how Bowser and the Bros. can fight together.
Underground Level: 'Tunnel Under Construction'. It's a large circuit that can be used to get around quickly as Bowser.
Underground Monkey: Many of the enemies are even more variations on the classic Mario foes, either at a cell level inside Bowser's body, or beefed up for Bowser himself to fight. Some are quite creative, while others are simply regular enemies under Fawful's Mind Control.
Any of the Giant Bowser fights, in which the Brothers must supercharge Bowser's adrenaline and turn him into a giant Godzilla-like destruction machine (probably a reference to either Giga Bowser from Smash Bros or the final battle of Yoshi's Island) to fight a huge enemy.
In regular battles, if Bowser takes enough damage he'll get angry and Turn Red (literally), raising his attack power but decreasing his defense.
Variable Mix: There are two tracks for everywhere in the game, one for when you're walking around outside as Bowser and one for when you're inside Bowser.
The Emoglobins all have very globin-ish and strange-ish speech patterns. They tend to use too much-ish of the "Globin" in the talking, but that is to be expected from creatures possessed of such a globin. IS THAT NOT GLOBIN?
The Moles tend to put 'bro' in every one of their sentences, leading to things like broski.
Mole (Upon seeing Giant Bowser): BRO NO!
Villain Protagonist: Bowser is a playable character. His designs aren't exactly altruistic, although the Mario Bros. do their best to manipulate him into not being a complete jerk all the time.
Wave Motion Gun: Dark Star uses this attack as both itself and the Fawful bug, requiring both brothers to jump onto Starlow during the charge-up time or else take major damage. The original Dark Star (and its X variant) will also pursue the brothers after the attack for just as much damage. Bowser's fire breath acts the same way.
Weapons That Suck: Not exactly a "weapon", but the Vacuum Block allows Bowser to suck up Blitties, small enemies, as well as parts of larger ones. It's far from sucky too, as almost all enemies that Bowser encounters are hampered by it in some way, or have an associated enemy that can be sucked up.
Broque Monsieur hates Mario since bashing in coin blocks "decreases their value" and makes business harder for him and thus will tell the Bros. to get out of his shop, albeit politely.
Parodied with the Wiggler. He tells Bowser to "take responsibility" for pulling up the Giga-Carrot by eating it for the Banzai Bill; when Bowser does, Wiggler gets mad and, rather than cough up the Bullet Bill as he promised, starts a fight! And the Koopa King needs to own up for his actions? Note that he got mad and attacked you not because you pulled the carrot up, but because you ate it, which he told you to do.
The Worf Effect: Like in every Mario and Luigi game, you fight Bowser at the beginning, and he's an absolute pushover. Justified this time, as his abilities are being weakened by Peach and Starlow. You even fight him later in the game at his full potential, and he puts up quite a fight.
Certain enemies do this, by going off one side of the screen and coming back from the other.
The Crawful enemy after it loses its teeth—the bean it tries to eat gets shot off the left side of the screen, only to land on its head from the right side of the screen.
You Are Not Alone: Bowser gets this at the end of the game from Chippy, who tells him that Mario & Luigi have his back. He doesn't hear them, and kicks butt himself regardless.
You Can't Thwart Stage One: You can't stop Fawful from taking over Bowser's Castle, kidnapping Peach, stealing the Dark Star, and awakening it. Even Mario and Luigi's hunt for the Dark Star consists of nothing but failed attempts to stop it.
It takes about 30 minutes of in-game progression for Bowser to learn the exquisite art of lying on the ground with his spiky shell pointing up for the purpose of defending from airborne attackers.
At no point in the game do Mario and Luigi ever have the ability to wear overalls, gloves, socks, AND shoes at the same time. Given, they eventually learn how to wear two or three of these four items at a time...