[[quoteright:340:http://static.tvtropes.org/pmwiki/pub/images/mario2.jpg]]

The second game in the ''[[VideoGame/MarioAndLuigi Mario & Luigi]]'' RPG series, released in 2005 for the NintendoDS. The Japanese name is ''Mario and Luigi RPG 2x2''.

The game changes a few game mechanics from the first one, and teams the brothers up with their time-travelling baby selves, who previously appeared in the ''VideoGame/YoshisIsland'' games as well as some of the sports game spinoffs.

Princess Peach travels to the past and is [[DamselInDistress promptly kidnapped]] when the Mushroom Kingdom of the past is invaded by the alien Shroobs. Our Heroes go into the past to find her and have to collect the [[PlotCoupon crystal shards]] that formed the Cobalt Star that was used to power the time machine in the first place while teaming up with their infant selves as well. Other than that, it's still pretty much the same game with some limited usage of the DS's features. The move-sets were altered to give each pair (bros and babies) unique items and moves, such as only the babies using hammers, and the Bros. moves in battle have been replaced by Bros. items instead.

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!!Tropes appearing in this game:

* AbsurdlyHighLevelCap: Level 100.
* AliensAreBastards: The Shroobs in general.
* AlienInvasion: By the Shroobs against the Mushroom Kingdom.
* TheAllSolvingHammer: Baby Mario constantly attempts to solve things by hitting them with his hammer.
* AndIMustScream: The fate of some Toads early in the game. [[spoiler:Poor Toadiko and later Toadbert. Fortunately, they are revived at the end, but that doesn't make it any less scary.]] [[spoiler:Also, [[SealedEvilInACan Elder Princess Shroob.]]]]
* AngryFistShake: Luigi when Stuffwell lands on him after coming out of the first time hole. Also when Baby Mario snaps Luigi back to consciousness with a hammer whack to the head. He wakes up and scolds the babies for it. This makes the babies cry, [[BigBrotherInstinct causing Mario to get angry once he wakes up]], [[UpToEleven causing Luigi to then cry]].
* ArcWords: The Shroobs continuously repeat a single two-character phrase throughout the game. Only later, when their speech is subtitled, do you find out what it means: [[spoiler:DESTROY!]]
* BadassAdorable: Baby Mario and Baby Luigi, of course!
* BadassAndBaby: The Mario Brothers and their baby counterparts, respectively.
* BadBoss: [[spoiler:Elder Princess Shroob frequently outright kills her henchmen during her (two, unless you count Shrowser) battles against the Mario Brothers...]] Her sister in contrast, though prone to yelling at her minions when she gets angry, is generally respected by her Shroob army who are willing to offer her drinks and build her a statue.
* BalloonBelly: Baby Mario can get like this by guzzling from a water source.
* BanditMook: Dark Boos, who steal an item from the Bros should their attack connect. They flee with it the next turn if not defeated in time.
* BeatThemAtTheirOwnGame: Baby Bowser teams up with his present counterpart to battle the Marios. While they're together, they have effective dual attacks, in addition with Baby Bowser providing Bowser with Mushrooms to keep himself fighting.
* BigBad: Princess Shroob. [[spoiler:Or rather, her older sister...]]
* BigDamnHeroes: [[spoiler:Kylie Koopa disguises herself as a Shroob and ambushes the ones ambushing the heroes on the mothership.]]
* BigEater: Baby Mario and Baby Luigi sure love Yoshi Cookies! So much that they eat all of Baby Bowser's ill-gotten gains. [[BigNo He isn't amused.]] Later Baby Bowser eats a whole ton of cookies and gets a tummy-ache.
* BossBonanza: The end features [[spoiler:a minigame fight with the Shroob Mothership, then normal boss fight with Princess Shroob, then her older sister, and then said sister's OneWingedAngel form. THEN there's a PostFinalBoss, Shrowser, after that.]]
* BossRemix: Bowser's battle theme remixes his leitmotif (which has two variations, for his young and adult selves).
* BuriedAlive: Petey Piranha does this to himself in his battle with him, although he only does it up to his oversized head.
* ButtMonkey: While the ''Mario & Luigi'' series loves to poke fun at Luigi, this game ramps it UpToEleven and makes him a veritable CosmicPlaything. Luigi is not only an IronButtMonkey (he takes a huge amount of abuse in game from enemies, objects, and Baby Mario's Hammer), but suffers through the entire game as a NoRespectGuy on top of it (a few of the Toads spend a not-insignificant amount of time suggesting Luigi leave the world-saving to Mario), and his baby counterpart himself finds it amusing whenever he is injured. The Toads don't even think too highly of him when everything is over [[spoiler:until they do cheer loudly for his name at the last second]].
* CallBack:
** When the quartet finds Kamek, he comments about how [[VideoGame/YoshisIsland badly it went for him to kidnap the babies before.]]
** Young Toadsworth reassures the brothers that [[YourPrincessIsInAnotherCastle Baby Peach is not in another castle]].
** After the disaster with his lab, the young E. Gadd says that he will safely [[VideoGame/LuigisMansion relocate to a lab at the edge of Boo Woods.]]
** Professor E.Gadd's solution for stopping the eruption of Thwomp Volcano is with the Hydrogush 4000, a giant [[VideoGame/SuperMarioSunshine FLUDD nozzle]].
* CarryingTheWeakness: Elasto-Piranhas, which are weak to fire, drop Bro Flowers, this game's Fire Flower equivalent.
* CatchPhrase: Stuffwell and his "BACK TO ADVENTURE!"
* ChekhovsGun: Subverted with [[spoiler:the giant Shroob key, which turns out to just activate a trap]]. Played straight with the [[spoiler:Hydrogush 4000]].
* ChekhovsGunman: [[spoiler:Toadbert and his drawing.]]
* TheChessmaster: Princess Shroob is very thorough with her plans for conquest. She anticipates the bros. movements and plans ahead for countermeasures like how they would try to rescue Princess Peach in Gritzy Caves [[spoiler:while she was disguised as her to conquer the kingdom in the present]] and how [[spoiler:if all else failed to terminate the brothers and she would get defeated, made sure the front gate of Shroob Castle would only open with the other five Cobalt Star shards imprisoning her sister]].
* ChromaticArrangement: The Shrooboids, oversized Shroob monsters that appear sporadically as bosses. This first is green, the second is blue, and the third is red. The localization appears to have missed this, instead grouping off the [[VideoGame/SuperMarioBros Red and Green Shrooboids as Elder and Younger]], while the Blue was recast as the otherwise unrelated "Shrooboid Brat".
* ClimaxBoss:
** The fight against Bowser and Baby Bowser, who kidnapped [[spoiler:the false]] Peach. Together they're pretty strong (being able to heal and attack twice a round) though it's possible to separate the duo to make the fight a lot easier.
** Before them, the fight with Petey Piranha qualifies, as he ate Peach and Kylie.
* CognizantLimbs:
** The final boss has ''seven'' parts, though only three -- [[spoiler:Elder Princess Shroob's legs, crown and head]] -- actually need to be destroyed.
** [[CherryTapping You still do one damage]] if you still hit [[spoiler:the head, which is the main target,]] and avoid taking out anything else. Said Final Boss has 3000(US)/2000(Everywhere else) HP.
* CollectionSidequest: Finding the buried beans to trade for goodies at Fawful's Shop.
* CoolChair: [[spoiler:Princess Shroob uses one during her battle with the Mario Brothers.]]
* ContinuityNod:
** Prince Peasley from ''VideoGame/MarioAndLuigiSuperstarSaga'' appears on a poster at the Shroom Shop. And Fawful runs a shop.
** Also, when you meet Kamek, he mentions once trying to [[VideoGame/YoshisIsland kidnap the Baby Mario Bros., and that it didn't end too well.]] Also from when Baby Mario and Baby Luigi find the Yoshis during the trip to Yoshi's Island, they seem to be acquainted with each other.
* TheCorruption: Shroobified enemies tend to have darker palettes, and a mixture of RedEyesTakeWarning and BlackEyesOfEvil.
* CrosshairAware: Sunnycide's egg-throwing attack is telegraphed by a targeting cursor [[ContinuityNod just like the one in]] ''VideoGame/YoshisIsland''.
* DarkerAndEdgier: This game is much darker than [[VideoGame/MarioAndLuigiSuperstarSaga the first one]]. You've seen the AndIMustScream trope in the list, above, right? [[FromBadToWorse It gets worse.]] In fact the game arguably does not get competition for the title of darkest Mario game until ''VideoGame/SuperPaperMario''.
** Aside from the AndIMustScream entry, you bear witness how the aliens are very prone to destruction and chaos, abducting innocent people to harvest their life force for their ''ships'', a giant Yoshi alien that swallows Yoshis to later turn them into monsters through modified eggs, the same aliens enjoying the suffering of others by holding massive celebrations by feeding their captives to Piranha Plants, polluting the water into alien swamp water, not showing any remorse for trying to attack babies, assimilating their bizarre culture into the kingdom, and lastly the implication that [[spoiler:Princess Shroob didn't care in the slightest to piece back the Cobalt Star to release her elder sister just so she could be in total charge of the invasion]].
* DeadlyDodging: How you beat [[spoiler:Shrowser.]]
* DeathMountain: The exterior of Thwomp Volcano. The interior, Thwomp Cavern is naturally lava filled. There is also the cliffs of Yoshi's Island.
* DefangedHorrors: As a ''Mario Bros.'' game, it clearly refrains from reveling in gruesome imagery, but there's some pretty horrific stuff going on that it glosses over. Take the Yoob, the giant Shroobified Yoshi that idly rampages across Yoshi's Island and consumes its inhabitants one by one. It doesn't actually eat them; located within its innards is a factory where the yoshis are converted, one by one, into Yoob eggs. Stuffwell and all four Mario Bros react with revulsion. The boss of that area is possibly the heart of Yoob, so you're also killing Yoob by killing Sunnycide.
* DemotedToExtra:
** Zigzagged with Bowser: His adult self is a big part of the plot in the previous game, but in this one, he only shows up for a boss fight before being thrown out of the plot. His ''younger'' self, however, is a major antagonist.
** Fawful went from being TheDragon to Cackletta in the previous game to being a shopkeeper in this one. He does, however, foreshadow his role as the BigBad of the ''next'' game...
* DiscOneFinalDungeon: You go through the Shroob Mothership about ten hours into the game.
* DummiedOut: The "Scoot-Bloop" enemy, which would have originally appeared in the Vim Factory.
* EarlyInstallmentWeirdness: Introduces the item-based minigame styled special attacks used in all future games, but takes the item metaphor literally and are used as consumable items, removing the BP stat entirely.
* EarnYourHappyEnding: [[spoiler:The Shroobs cause a lot of destruction and several of the people the Mario Bros. meet are shroobified or have their vim sucked out of them, but in the end, after all the crap the world of the past went through, the bros' efforts pay off and the Shroobs are defeated, undoing all the damage they caused.]]
* EasilyThwartedAlienInvasion: An entire alien army is bested by four plumbers, and two of them were infants! Hell, [[spoiler:one of said infants' ''tears'' were all it takes to undo the damage they've done]]!
* EstablishingCharacterMoment: Baby Mario establishes his personality in Baby Bowser's Castle by happily leaping from a great height to meet up with the Mario Bros. However, Baby Luigi is much more hesitant and doesn't jump until the Mario Bros. assure him that he will have a safe landing by using Stuffwell.
* EvilCounterpart: The Shroobs often act like this to the Toads, even having an enemy ingame known as the Shroobsworth. The Shroobs also have evil counterparts to other Mario characters, such as Princess Shroob to Princess Peach, Yoob to Yoshi, and the Shrooboids to Mario and Luigi (note that the elder one is red and the junior green).
* EvilDetectingBaby:
** [[spoiler:When Princess Shroob arrives in the Mushroom Kingdom disguised as Princess Peach]], Baby Peach is seemingly the only one to recognize her as she cries right in front of her.
** Also, Baby Luigi. He cries when he sees the spirit of the Cobalt Star [[spoiler:which is really the Elder Princess Shroob sealed inside]].
* ExoticEntree: When Baby Bowser is choking on stolen cookies, he is offered milk from Kamek, who insists it's from an evil cow. It's goes well with good cookies apparently.
* ExpositionFairy: Stuffwell the talking suitcase, and he would be the first of many.
* TheFaceless: Princess Shroob's face is not actually seen up until the point you enter the Koopaseum. [[spoiler:Later, when she poses as Peach, a Shroob mushroom on her face is part of her disguise. With a wig, dress, and gloves, she looks exactly like Peach.]]
* {{Foreshadowing}}:
** All those times when the Cobalt Star behaves unusually or makes the Shroobs react violently to it is not because it's acting up randomly, but it's because [[spoiler:the Elder Princess Shroob is trying to break free from her imprisonment and trying to communicate to her subjects (in this case the imprisoned and defeated Junior Shrooboid) to release her]].
* When Princess Peach returns to Peach's Castle. [[spoiler:Baby Peach immediately starts crying.]]
** The above only gets further foreshadowed when Baby Luigi [[spoiler:is the only one who starts to cry when the "spirit" of the Cobalt Star starts talking to them in the Star Shrine]].
* In the Star Shrine, Toadbert asks the player to wipe off the smudges off of the picture that he showed them earlier. [[spoiler:It reveals that there was a Shroob witness to Peach's battle with the Shroob princess.]]
* FromNobodyToNightmare: Play any other game featuring Petey Piranha as a boss besides VideoGame/NewSuperMarioBros1. He's a simple WarmUpBoss with little plot importance in each, with the trend continuing in VideoGame/MarioAndLuigiPaperJam (albeit with a stronger counterpart). In THIS game, however, he eats Peach and Kylie, is a ClimaxBoss, and is rather challenging in battle. (So, in a sense, the trope is inverted.)
* FissionMailed: You have to lose to the Shroobs in Hollijolli Village so that the Baby Mario Bros. can join you.
* {{Flanderization}}: Luigi's [[LovableCoward cowardice]] and [[ButtMonkey ineptitude]] are inflated to their limits in this game, to the point where [[ManChild he seems as childish as the babies.]]
** Toadsworth goes both ways. In''VideoGame/SuperMarioSunshine'', he was obviously worried about Peach, but remained somewhat level-headed about it. Come this game, his past self is paranoid to the point of believing his present self is trying to kidnap Peach. Once the misunderstanding is cleared between the two, Past Toadsworth tries to flatten Baby Peach with their Bros. Ball move while Present Toadsworth is against it. They succeed, leaving Present Toadsworth in shock while Past Toadsworth teaches the Baby Cakes move to the Marios by himself.
* FunnyBackgroundEvent: In Gritzy Desert, while Kylie Koopa is talking to Mario, Luigi is being chased by a Shroob and the babies are pursuing it with hammers. [[ButtMonkey Luigi also gets hit by the hammer and eventually collapses with a "Mamma mia!"]]
* GenerationXerox: This is where Baby Bowser starts looking exactly like Bowser Jr., his future son.
* GoingForTheBigScoop: Kylie's personal goal in the game is to write a book about the Shroob Invasion. Although she gets eaten by Yoob and Petey Piranha, [[spoiler: she succeeds.]]
* GoldColoredSuperiority: The game had a golden version of a early mook that appears halfway through the game. Although this one has lower health than the original, it compensates by having a higher defense and attack power.
* GreenHillZone: As soon as the adventure really begins the brothers are transported to a grassy area on the outskirts of Hollijolli Village. Cue the MoodWhiplash as soon as the brothers reach town. The main area of Yoshi's Island is also rather green.
* HopelessBossFight: When Mario and Luigi first encounter the Shroobs, they get drawn into a fight with three Shroob enemies. Each of these enemies has about 15 HP and a simple attack pattern... but there's also an UFO flying overhead with a countdown timer set to three turns (after which it'll take the bros out ''[[DeathFromAbove but good]]''). At their current power level, it's barely possible to take down ''one'' of these guys in that time frame. \\
\\
This segues into the Babies pulling off a BigDamnHeroes and using these same three Shroobs as a tutorial fight for Bros. Items.
* HubLevel: Princess Peach's Castle in the present functions as this since the characters never venture outside of the present-day castle. Notably enough, this is the only game in the series to feature a HubLevel, as all the other ones feature interconnected overworlds instead.
* IHatePastMe: Bowser ends up meeting his past self in Thwomp Volcano, and the two of them proceed to fight over which one gets to use the place as an evil lair. They eventually decide to team up, but neither one ever figures out the other's identity.
* IntrepidReporter: Kylie Koopa is always out for the next scoop.
* IronicNurseryTune: Hollijolli Village's background music is based around a depressing-sounding version of Jingle Bells. Later, Toad Town has the same depressing music,
* KilledToUpholdTheMasquerade: Not exactly "killed", but the Shroobs have a ''frustratingly'' chronic habit of invoking this. Whenever a character tries to explain a single word about the Cobalt Star [[spoiler:and what it contains]], he or she '''will''' be [[AndIMustScream shroobified]] before getting to finish. The only exception is [[spoiler:[[DamselInDistress Princess Peach]] herself, who instead gets interrupted ''constantly'' until [[SpannerInTheWorks Baby Bowser]] fully reassembles the star]]. Toadbert is initially an exception because he's suffering from amnesia, though he does show her a picture detailing Peach's battle with what appears to be Princess Shroob.
* LargeHam: Bowser, as usual. Given a twist by his unintentional fall through a [[TimeyWimeyBall Time Hole]], where he meets his younger self, Baby Bowser (who can only be described as a ''Small'' Ham). [[spoiler:The two team up and battle the Bros. despite [[DramaticIrony both Bowser and Baby Bowser being unaware of who the other is]].]]
* LastVillainStand: [[spoiler:The Elder Princess Shroob.]]
* LethalLavaLand: The interior of Thwomp Volcano.
* LostWoods: The Toadwood Forest which is also quite creepy being set at night, and not to mention what is happening to toads here.
* MakeMyMonsterGrow: The Shroobs do this to Yoob. One can only wonder how the subsequent WombLevel properly functioned prior to the size change.
* MarathonBoss: A lot of bosses have a ton of HP, and thus they're very long, [[{{Padding}} to the point that they can feel like they drag on for too long.]] The biggest example of this might be the FinalBoss battle, where you fight the BigBad [[spoiler:and then her older sister, the latter of which has two forms, which is shortly followed by a PostFinalBoss fight against Bowser.]] It's common for boss fights to take easily about ten minutes, but the final boss battle can easily take over an ''hour,'' especially if you didn't grind a lot.
* MineralMacGuffin: The Cobalt Star shards.
* MoodWhiplash:
** The destroyed Toad Town section of the game is immediately followed by the celestial peace of Star Hill.
** When you first arrive in the past, the first area has a bouncy, lively rendition of the original Mario theme, but then you get to Hollijolli village, where you have a sad version of "Jingle Bells".
* MyFutureSelfAndMe: The gameplay hook for this game has the adult and infant Mario Bros. teaming up inside and outside battle. Having both generations of Bros. together in battle lets you use attacks and Bros. Items in new ways, such as double jumps and fireballs that can target air enemies. Bowser and Baby Bowser also have their own boss fight, and have multiple team attacks they can use on the heroes.
* NiceJobBreakingItHero: [[spoiler:Assembling the Cobalt Star, which takes 95% of the game, undoes everything Peach sought to avoid from the start of the game and unleashes the Elder Princess Shroob.]]
* NiceJobFixingItVillain: [[spoiler:Princess Shroob's plan to take over the modern day Mushroom Kingdom while disguised as Peach would have probably been much more successful had Bowser not shown up and attempted to kidnap her, hurling them both back into the past in the ensuing chaos.]]
* NonstandardGameOver: The only GameOver that can happen outside of battle. [[spoiler:When you get to use the Shroob flying saucer, [[UnexpectedGameplayChange its controls need the plumbers to hit four blocks by jumping]].]] If you fail, the [[spoiler:flying saucer]] falls as [[NothingIsScarier the screen fades to black]] and the plumbers freak out, while you get mocked by Princess Shroob's creepy laughter.
* NoodleIncident: Used by the gate to the Star Shrine when it talks to Luigi.
* OcularGushers: Baby Luigi, Baby Mario, Baby Peach, and Luigi all do this frequently.
* OffscreenMomentOfAwesome: The events detailed during TheReveal about the Cobalt Star surely must've been a sight to behold.
* OneWingedAngel: [[spoiler:The Elder Princess Shroob.]]
* OrcusOnHisThrone: [[spoiler:Princess Shroob attacks the brothers directly only after they anger her enough by destroying her mothership.]]
* PerpetualFrowner: Peach, for some reason. [[DarkerAndEdgier Given the scenario, however...]]
** She ''does'' look perfectly happy in her official artwork, though.
* {{Plothole}}: Unfortunately for the game's reputation, the incident that kicks everything off is one. Princess Peach and a small retinue of Toads embark on the inaugural voyage into the past with Professor E. Gadd's time machine... only to get kidnapped because they traveled to a date ''in the middle of an AlienInvasion that nobody remembers at all''.
* PointOfNoReturn: '''''Nastily''''' used in case you do not open up the pipe to the underground level of Present's Peach's Castle after you clear Thwomp Volcano from the inside. The bros will never be able to access the upper levels and stay locked out from every other area except Toad's Town and Star Shrine from the past. You can only fix this by ''starting over''.
** You can only explore the Shroob Mothership once. After that, you can't return to it.
** Used and subverted: The fight against [[spoiler:the Shroob Mothership]] is the point of no return, but Stuffwell warns you about it. Even better, after you pass the PONR, he gives you the possibility to go back to before the fight, asking you every time you hit a save point.
* PortalToThePast: They conveniently start appearing all over Peach's Castle after E. Gadd's TimeMachine returns useless.
* PostFinalBoss: [[spoiler:When Mario, Luigi, and the babies return to the present after defeating the Elder Shroob Princess, what's left of her possesses Bowser (turning him into "Shrowser") for one last battle.]]
* PressXToNotDie: [[spoiler:All you can do in the final fight against Shrowser is dodge/deflect his attacks long enough for him to [[TacticalSuicideBoss whittle down his own health bar]].]]
* PunctuatedForEmphasis: Fawful. I WILL! HAVE! FURY!
* PunnyName:
** Prof. E. Gadd. Egad. [[DontExplainTheJoke Geddit?]]
** Sunnycide, a giant egg, as well.
* SadBattleMusic: The FinalBoss music.
* SchrodingersCat: The Copy Flower makes practically an infinite number of clones of the bros. The one that messes up is the real one, so theoretically all of the Bros. that attack are real and fake at the same time (until you mess up, anyways).
* SealedEvilInACan: The [[spoiler:Cobalt Star]] holds [[spoiler:Elder Princess Shroob]].
* SealedEvilInASixPack: The protagonists spend the game collecting several shards of the Cobalt Star. Only when they collect and put the pieces together do they realize that the star [[spoiler:actually contained the leader of the invading aliens who was trapped inside by Princess Peach, and that by putting the star together, they release her.]]
%%* SequelDifficultyDrop
* SesquipedalianLoquaciousness: Stuffwell is rather fond of this.
* ShiftingSandLand: The Gritzy Desert. Also features some ruins and the Koopaseum giving a TempleOfDoom feel.
* ShoutOut: The Snoozorb's appearance and sleepy motif brings to mind an infamous Metroid boss.
** There are various references, such as the opening, the mothership crash and Princess Shroob's chair, that pretty much make the game a Mushroom Kingdom [[http://tvtropes.org/pmwiki/pmwiki.php/Literature/TheWarOfTheWorlds War of the Worlds]].
* SlippySlideyIceWorld: The main area of Hollijolli Village is a snowy town that is also stuck in a perpetual Christmas.
* SoleEntertainmentOption: The arcade housed in a freakin' ''VOLCANO''
* SomeDexterityRequired: Because the game uses all four buttons for its ActionCommands, it can become very disorienting and easy to lose what button press you need to input next if only because of [[DamnYouMuscleMemory muscle memory]] alone. Some even say that the green shell, the first bros. move, is one of the ''harder'' ones in the game to pull off because of this.
* SoundtrackDissonance: Unlike how you'd expect a happy Christmas-themed music track from a place called Hollijolli Village, [[https://www.youtube.com/watch?v=Zb4bz4kkNhM it actually sounds extremely depressing once you do get there after it was razed to the ground by the Shroobs]].
** The [[http://www.youtube.com/watch?v=ujQwJdykk68 ending credits theme]], which sounds downright ''sinister'' compared to what you'd expect from an ending theme in a video game.
* SpannerInTheWorks:
** [[spoiler:Like in [[VideoGame/MarioAndLuigiSuperstarSaga the prequel]], Bowser causes everyone a headache by choosing to kidnap Princess Peach at the worst possible moment. This time it turns out to be a ''good'' thing however, as "Princess Peach" was actually a disguised ''[[BigBad Princess Shroob]]''.]]
** [[spoiler:Baby Bowser plays this trope in a much worse fashion, suddenly appearing in Shroob Castle to assemble the Cobalt Star after the Bros. were told not to. Cue FinalBoss.]]
* SpeakingSimlish: Everyone. The Bros' version sounds vaguely Italian, with a few recognizable words; the Shroobs are entirely tonal.
* SuckingInLines: Serves as a tell for the Snoozorb enemy. If the lines are spinning, the laser they shoot will go overhead, meaning that you shouldn't jump.
* SugarApocalypse: What happens to Toad Town and Hollijolli Village. The latter is probably more unsettling, as it happens right as Mario and Luigi are watching, and right during Christmas.
* TakeThat: The {{Brainwashed}} Hammer Bros. speak entirely in 1337-speak in the English release. After they're freed from the mind control, one of them remarks "Seriously, who talks like that?"
* ThatLiarLies: The Star Gate accuses [[spoiler: Luigi of this when Luigi was only given three options instead of 4: Everyone! The Star Gate is the true liar but it's all part of a test.]]
* ThemeNaming: All Shroob lifeforms and otherwise Shroobified enemies will be indicated not only by their appearance but by the structure of their names. Natural Shroobs tend to have the full word "Shroob" in their name, while Shroobified classic Mario Bros. enemies tend to have "S-", "Shr-", or "-oob" appended somewhere to their name.
* TimeTravel: The plot is half this and half AlienInvasion.
* TimeyWimeyBall: It's probably best not to analyze this at all, as the time travel doesn't even try to make sense.
** There's a great timey-wimey scene that combines MeanwhileInTheFuture with RippleEffectProofMemory -- The Bros give younger Professor E. Gadd a EurekaMoment, and we cut to older Professor Gadd, who is ''having the idea at the same time, and is aware that it's because his memory is changing''.
** A less apparent example occurs with [[spoiler: Princess Shroob disguising herself as Peach to take over the Mushroom Kingdom of the present. It is quite clear that the Mario Bros. and their baby counterparts are the only people in the Kingdom capable of fighting off the Shroob invasion, so every time they return to the present before the Shroobs are defeated, they are leaving the past Kingdom completely vulnerable to Shroob takeover. Princess Shroob shouldn't ''need'' to go to the present because the present Peach's Castle should be Shroob Castle without anyone to fight against it over the timeskip.]]
** The Shroob invasion as a whole. There's absolutely no record of it, which is completely bonkers, because the Shroobs were destroying everything they looked at. Even if you assume current normalcy is because the Shroobs were defeated in the past, that only raises questions because it shouldn't have been the Mario Brothers who solved the problem; as the first example indicates, Professor Gadd's altered memories indicate the Brothers were never there at all in the first place. [[ContinuitySnarl Headaches ensue]].
** A record of their defeat does appear even before the final battle is fought. In the present, a Toad comments about the invasion by a book [[spoiler:Kylie Koopa did manage to write]] and how the alien threat was repelled. He admonishes the brothers from asking him how it went down since they are dealing with it, though...and also because the last page about it was torn.
* UndergroundMonkey: Many enemies and bosses are [[TheCorruption "Shroobified"]] versions of standard Mario enemies. One good example is the [[http://www.mariowiki.com/Tanoomba Tanoomba]] (itself an Underground Monkey of the basic Goomba), which gets a faster Shroob variant (the ''[[http://www.mariowiki.com/Tashrooba Tashrooba]]'') in the final dungeon.
* VileVillainSaccharineShow: The Shroobs. Murderous invaders who attack innocent civilians, entrap Toads and drain their [[LifeEnergy vim]] for ''UFO fuel'', and turn the entire world into {{Mordor}}. They express no concern for the concept of innocents and are quite happy to attack even Baby Mario and Luigi. [[ArsonMurderAndJaywalking And they attack Hollijolli Village right on Christmas Eve.]]
* VillainousBreakdown: Given what a short temper Princess Shroob has, it's not surprising that she eventually goes berserk following the destruction of her Shroob mothership...
* WalkingSpoiler: [[spoiler:Elder Princess Shroob.]]
* WarmUpBoss: Baby Bowser (for Baby Mario) and Junior Shrooboid (for Mario). [[ZeroEffortBoss Naturally, you can't lose either fight.]]
* WeaksauceWeakness: How to dispose of evil toxic fungal life-sucking alien Bio-Weapons? [[spoiler:Cry on them.]]
* WhamLine: A couple in a row. Throughout the game, you collect the Cobalt Shard pieces and presumably try to save the world with it. Peach has the final Cobalt Star piece in her possession, and could regain its original shape...and then she says something that changes the scene entirely.
--> Peach: [[spoiler: "But I cannot allow that to happen!"]]
** Shortly afterwards, Baby Bowser puts it together himself, and then we get this line from Princess Shroob that finally reveals what the Cobalt Star's true purpose is:
--> Princess Shroob: "Now it's your turn...[[spoiler: [[OhCrap SIS]]-[[SealedEvilInACan TER!!]]]]
* WhatHappenedToTheMouse: ''Tons''. [[spoiler:The captured toads, though revived at the end, are never directly seen rescued, Yoob is literally left hanging, Junior Shrooboid just vanishes, and Toadiko and Toadbert are never seen returning to the present.]] The last one, however, is addressed in the sequel. [[spoiler:Toadbert made it back.]]
* WhenAllYouHaveIsAHammer: Baby Mario's solution to everything is by banging it with a hammer, or when he wants to do pranks almost all the time.
* WhereItAllBegan: The endgame takes place in Shroob Castle, which is the Shroobified version of Peach's Castle, the first area you explore. [[spoiler:The PostFinalBoss fight with Shrowser also takes place in Peach's throne room, where you first fought Baby Bowser and Junior Shrooboid at the very beginning.]]
* {{Wingdinglish}}: How the Shroob language is presented.
* WombLevel: Yoob's stomach.
* WouldHurtAChild: None of the bosses which are obviously sapient show any hesitation in attacking Mario and Luigi while they are ''carrying their baby selves on their backs''. Not to mention that [[TimeParadox killing their baby selves would affect other characters more than just emotionally]].
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