History Undertale / TropesGToN

* GagDub: [[https://www.youtube.com/playlist?list=PLSRV2j8i5ybaxhBYzBVbHiIV6zUBZorVC Undertale With Voices: Genocider]] and [[https://www.youtube.com/playlist?list=PLSRV2j8i5ybYn1QWIhilFjtiFKpFZ03JC Undertale With Voices: Pacifist]], both brought to you by WebVideo/TheWithVoicesProject.

* HealingBoss: Attempted by [[FinalBoss Omega Flowey]] at the end of his boss battle. After [[BreakingTheFourthWall exploiting SAVE files to attack Frisk]], he uses one to heal himself to full health after you beat him. [[spoiler: The souls he absorbed then revolt and tear him open from the inside, defeating him again and removing his power over the game itself.]]

* LawyerFriendlyCameo: A version of the famous [[Webcomic/RageComics Trollface]] (which is, in fact, copyrighted by its creator) makes a cameo at the end of [[spoiler:Omega Flowey's battle, being displayed on the TV screen]]. It's ''just'' barely distinctive enough from the original.

* IncompetenceInc: MTT Resort, as Burgerpants puts it, is a "Labyrinth of bad choices." Right as you enter the lobby, you're greeted by a fountain with the image of Mettaton spitting water right onto the carpet. The residents never get their room service, the janitor is too busy cleaning up his own messes that he can't clean anything else, the elevator's completely busted, and you have to reserve your dishes and silverware to eat at the restaurant. Not to mention that the store sells parfaits and burgers made out of ''sequins and glue''. Burgerpants mentions that Mettaton vetoes any actual improvements they make because "that's not how they do it on the surface."

* GreenGators: Swampy is green. So are all the other alligators that show up in the game.

* IAteWhat: Plenty of the food items in the game are made of questionable ingredients. Hot dogs made of water sausages, burgers made of sequins and glue, steak made of anything but meat, junk food made of actual garbage…

* MultipleEndings: Three basic variants, though the phone call at the end of a Neutral run has several sub-variants of its own. None of these have official names; every ending's name is a FanNickname.

-->[[spoiler:'''Alphys:''' S-sometimes you've just got to, uh... S-stop going after furry boss monsters and, uh... J-just get to know a really cute fish...? ... [[BlatantLies It's a metaphor.]]]]

** In the UsefulNotes/NintendoSwitch version, [[spoiler:a secret room can only be entered by opening cyan and red doors via pressing the Joy-Cons' analog sticks a certain way (cyan and red being the colors most commonly associated with the left and right Joy-Cons respectively). This continues in the battle with [[BonusBoss Mad Mew Mew]], where the SOUL is split into cyan and red halves, both of which are controlled by their respective Joy-Cons.]]

** Being defeated by the Neutral Final Boss causes him to taunt you during the Game Over screen after Asgore says his usual line.
** During the final boss of the No Mercy route, trying to spare the boss at a specific point will cause him to [[ISurrenderSuckers kill you with an unavoidable attack]]. The resulting game over screen will have Dogsong play instead of the regular Game Over music while the boss will assert that, after all of your genocidal actions, he refuses to allow the battle to resolve peacefully.

** Getting a combination of endings affects the outcome of another. [[spoiler:In the Genocide ending, the Fallen Child kills everything and decides to move on to another world... the reset world of ''Undertale'', which would only reset if you took a DealWithTheDevil with them. Doing a Pacifist run afterwards heavily implies the Fallen Child's still in control, has taken down every main character, and is moving on to the surface world... and other worlds.]]

* GenderNeutralWriting: The main character, Napstablook, Monster Kid, and [[spoiler:the Fallen Child]] are only ever referred to using gender-neutral pronouns.[[note]]It also makes translations to other languages outside English, Japanese, Korean and Chinese next to impossible, since most languages don't have this.[[/note]]

** The player character's name is actually [[spoiler:Frisk, and the character you named at the beginning is really the Fallen Child.]]

** When you initially defeat [[spoiler:Photoshop Flowey in the Neutral run]], he declares he is the God of this world. Of course, this is right before [[spoiler:the Human souls he stole rebel against him]].
** The final boss of the True Pacifist run proclaims himself to be "The Absolute God of Hyperdeath" after gaining nigh-omnipotent power from [[spoiler: absorbing the six human souls as well as the soul of nearly every monster in the Underground.]]

** [[spoiler:The Pacifist route ends with [[EverybodyLives everyone down to the last random battle alive and happy]], all the bosses becoming friends with each other, and the villains ([[WhiteAndGreyMorality such as they are]]) acknowledging their mistakes and prepared to seek redemption if they didn't earn it already. And the PlayableEpilogue shows how happy all the monsters are with their new lives. The only dark patches are that Asriel is ultimately resigned to the fate of turning into Flowey once more, and nothing prevents YOU from resetting the save file and erasing all that happiness, though the game actively discourages you from doing so (ironically via Flowey himself begging you not to do it)[[note]]If you really, ''really'' want to, you can make a copy of the Pacifist route save files and keep them around![[/note]].]]
** Somewhat interestingly, there's a Golden Ending ''within'' the Golden Ending. If you ACT with monsters in such a way that they're happy with you when you spare them (and monsters you never encounter aren't shown at all), the text in the credits roll will [[spoiler:show how successful they were at integrating into human society, with white text being "doing alright" and yellow meaning "found a perfect calling".]]

* GoodFeelsGood: Whenever the game isn't judging and[=/=]or guilt tripping you for being a jerk, it's instead encouraging, supporting and appreciating you for being good, or even just not being bad, and it's very good at making you ''care'' about your choices.

** Mettaton, if you get the Ratings past 10,000. It's only temporary, though... he's just out of battery life.

** [[spoiler:Both Papyrus and Sans keep their permanent skeletal grins as you kill them in the genocide route; Papyrus because [[ThePollyanna he still believes you can be a better person]]]].
* GrayAndGrayMorality: The Neutral routes. On one hand, the PlayerCharacter is trapped in a fairly hostile world where most monsters are out for their blood, even if the monsters themselves are {{well intentioned extremist}}s trying to secure their own freedom from the Underground, or attack due to [[BlueAndOrangeMorality animal instincts]]. On the other hand, you yourself can choose to respond to this hostility in a ruthless manner by using lethal force. At best, this only results in you causing the death of [[spoiler:the Monster King Asgore, as he must be fought in order to finish the game, and possibly Flowey too, after you fight him]]. At worst, you've left a massive trail of bodies behind you and thrown the kingdom of monsters into despair and disarray. Most new players will likely end somewhere in-between on their first run, making them {{Anti Hero}}es in a world where EverythingTryingToKillYou.

** Flowey mentions at several points that [[spoiler:before you showed up, he used his ability to SAVE to toy with all the characters this way, altering reality so that all of them are technically in one without even knowing it. Assuming that it worked the same way it does when you SAVE, none of them have any direct memories of previous versions of the timeline, but do have foggy recollections of them similar to deja vu or half-forgotten dreams.]]
** On a more meta level, [[spoiler:because every subsequent playthrough on the same save file canonically takes place in the same in-game universe, you can perpetuate this cycle yourself by playing the game and then resetting. Once again, with the exception of [[GreaterScopeVillain Flowey]], none of the characters remember this directly, but do have enough awareness of it to alter their dialogue in several places.]]
** Both these examples have a significant curveball thrown into them: [[spoiler:[[HiddenDepths Sans]]. Sans is aware of the fact that he exists in a universe that can be altered and reset at any given moment, and how significantly it affects his character seems to vary based on player actions and AlternateCharacterInterpretation. At the [[DespairEventHorizon height of his despair]] at the end of a Genocide route, he tells you that living with his knowledge has [[GoneMadFromTheRevelation left him in a state of existentially-driven apathy and depression]]. He then goes on to say that even getting the GoldenEnding and making it to the surface world doesn't appeal to him anymore, because it would just look like a setup for a HopeSpot in his eyes; the player is inevitably going to reset sometime anyway, right?]] As a result, the only way to truly free him from this loop is to [[GameplayAndStoryIntegration never play the save file again after getting the best ending]], a move that the game actively encourages you towards and many players have admitted to doing, some going so far as to preserving the file in a thumb drive just to be safe.

** Figuring out how to defeat the bosses non-lethally in many cases involves paying close attention to clues from other [=NPCs=] and to how the boss reacts to different actions. The only way to spare Mettaton EX, for instance, is to [[spoiler:either get your ratings above 12,000, or survive until his limbs fall off and get your ratings above 10,000.]] You're never given any obvious hint for this, and new players might assume [[spoiler:the ratings were just for show.]]
** Sparing Undyne - the game doesn't really give much of a hint that you even ''can'' run from her, or that if you ''do'', that it will allow you to spare her. [[ViolationOfCommonSense Typically, you don't run from bosses in these kinds of games]].

** There's a way to get into Sans's bedroom. [[spoiler:Once you reach the Last Corridor in a Pacifist run, talk to him to receive his judgement 4 times by reloading and he will give you the key.]] It does make sense, but only in retrospect -- who would think to do something like that if they didn't already know the game acknowledged it?
** In the Pacifist epilogue, you can find [[spoiler:Asriel]] all the way back at the patch of golden flowers in the Ruins where the game started, where he gives backstory about [[spoiler:Chara]] and realizes they weren't as good as he remembered. The Ruins are inaccessible until the epilogue, and he only appears before you see the credits, since otherwise he'll [[spoiler:have turned back into a flower.]]

** Arguably, the way to achieve the worst ending (i.e. No Mercy / Genocide route). While the game guides the player quite clearly to the best ending (Flowey always tells you what you missed at any neutral ending you get, unless you've killed him), even the existence of such a worst ending is not clearly hinted, nor the way there instructed. This is deliberate, because it means that there is nearly no chance a player will end up on the route accidentally; a major theme of the route is that the player themself is choosing to kill absolutely every monster (despite it being unnecessary and tedious) because they want to know what happens if they do.

** In the No Mercy route, [[spoiler:Undyne takes a blow for the Monster Kid that visibly cuts her battle sprite in two, from shoulder to hip. Her upper half begins to slowly fall off...until she reforms herself for the real boss battle.]]

** A heartbeat plays in background of the final scene of any Genocide playthrough, where the player has killed every single NPC the game allows.

** There are only two fully voiced lines in the entire game across all routes. The longer of these occurs [[spoiler:during a conversation with Flowey during the No Mercy run, where he mentions wiping out the world. Without appearing in the text box, a horrible voice says "that's a wonderful idea!"]] The other is [[spoiler:a robotic “OH YES” that plays when Mettaton premieres his EX form.]] Most players will find that two is ''plenty''.

** [[spoiler:The Fallen Child]] gets two really creepy themes. One is the menacing [[https://youtu.be/uGqvpMQQ48o "In My Way"]], which plays during two encounters with monsters that will not attack you and can be instantly spared... or instantly killed. And the other is a [[https://youtu.be/93q3irqZxxo warning drone]] noise that indicates you've finally met your match at the end of a Genocide run.

** [[spoiler:Asriel after his HeelRealization]] decides to do the right thing and [[spoiler:give all the monsters their forms back, at the cost of reverting back to a soulless flower. He also refuses to go with Frisk and his parents to the surface, because he doesn't want anyone to see him turn into a horrible monster]].

-->[[spoiler:'''Asriel''': [[WhamLine You're not actually Chara, are you? Chara's been gone for a long time.]]]]

** Mettaton [[spoiler:turns on Alphys when she recruits him to be the "bad guy" so that she can save you from him and he decides it's more fun and exciting to ''actually'' be the bad guy who doesn't create openings for her solutions. More notable in that she created his robotic body, which is the primary reason you can't defeat him, since you have no magic and physical attacks can't hurt him.]]

** The final boss of the True Pacifist Route seems to present itself as this. You're even told, right before the battle, that it should be technically impossible to defeat him, and that's ''before'' he [[OneWingedAngel powers up]]. [[SubvertedTrope There is a catch to this]]. [[spoiler:The player can't die. Every time your HP runs out, your heart [[StealthPun refuses]] and you continue the fight. So it will continue until you win by saving all your monster friends...and, eventually, Asriel himself – you don't ''defeat'' him, you [[TakeAThirdOption use his newfound power to feel love and compassion to remind him of why he's doing any of this in the first place.]]]]

** Downplayed example: While Undyne ''can'' be defeated in a Neutral route by attacking her until she dies, she's the ''only'' enemy outside No Mercy who cannot be spared by any means. Fortunately for players who are unwilling to kill her, she's also the only boss (other than Toriel) who can be run from...
** Asgore seems to be this way in a Pacifist run. The 'Hope' in this situation wouldn't be to win, but to spare him and resolve the fight peacefully – [[spoiler:and his first move on his first turn is to take his trident and ''shatter the MERCY button'', removing it from the screen entirely. You're then forced to use the FIGHT button, possibly for the first time in the whole game, once ACTing stops progressing the battle and you run out of items to use.]]

** For the Player, doing a Pacifist Run [[spoiler:after No Mercy and the world has been ended]]. Surely you can make things right after going so horribly wrong. Unfortunately, you [[spoiler:sold your and Frisk's souls to the Fallen, so that they appear in every subsequent run]]...

** Several monsters who assumed you were evil and attempted to kill you in a neutral or pacifist run will, in a No Mercy run, when the character is ''genuinely'' evil, instead be incredibly trusting of them and simply offer to let them go without a fight, only to be murdered in cold blood. Justified in that if you have been sparing everyone, you will continue to look like a human, but if you have been killing everyone, you slowly start to look monstrous. Humans, as per the narrative, are the enemies of the monsters. There are also a few monsters who are less this and more GenreSavvy, as they're aware that if they try to stand in your way you ''will'' kill them, and they hope that by sparing you, you'll stop seeing them as an obstacle and move on.
** [[spoiler:Papyrus]] plays with this. If you ''do'' choose to spare during a genocide run, he will admit that he was a little afraid that you weren't going to accept – and give – mercy, and is glad you did. There's also a little bit of implied fear of HeWhoFightsMonsters on the boss' end, as he's more willing to spare you and die than kill you in cold blood.

** At the end of your first Neutral run, [[spoiler:Flowey ganks Asgore's soul (after killing Asgore himself, if you opted not to), steals the six human souls, and crashes the game. When you restart it, the intro story is interrupted by a glitchy mess, and the save file, instead of your name and location, now reads "Flowey: My World". Eagle-eyed players will also note that the game's title bar now reads "FLOWEYTALE".]]
** After defeating the final boss in a No Mercy run, you no longer control your character in battle, [[spoiler: the First Fallen Child does.]] Walking forward to talk to Asgore leads to attacking and killing him regardless of the player's inputs, and then doing the same to [[spoiler: Flowey]] even as he begs for mercy. Upon killing him, the game will no longer return to the overworld, and instead shows a black screen- the battle screen with no enemies left to fight.

** The Neutral Route final boss [[spoiler:Photoshop Flowey spams attacks and abuses savestates to leave you with 1 HP when he thinks he's won. Running into the circle of bullets while he's doing his speech doesn't hurt you and only annoys him. In fact, Flowey seems to be very fond of leaving you at 1 HP and gloating before sending a killing blow.]]
** The TrueFinalBoss pulls this off [[spoiler:when trying to destroy the entire timeline. You're only alive because you're that determined. He will later exaggerate this trope by reducing your health to a minuscule fragment of a HP.]]

* HumansAreBastards: The game builds it up this way at the start – the humans imprisoned the monsters at the start of the backstory because they feared a preemptive strike and decided to attack first. In fact, many people (like Undyne) assume you're a terrible person just because you're a human. [[spoiler:This is later subverted: humans are extremely accepting of monsters in the epilogue, and judging by how fast monsters integrated into society, it seems like they want to repent for their previous actions. In fact, when you find out that humans killed a monster who was bringing the body of a human child back to the child's village, the narration states that they believed the monster had killed the child. The human you play as, Frisk, is even an AllLovingHero by nature. The ''only'' human character in the story that qualifies as evil is [=Chara/The First Child=] or potentially the Player, and even their case is [[AmbiguouslyEvil highly ambiguous:]] at best they're just a traumatized[[TheSociopath sociopathic]] WellIntentionedExtremist[[note]]and, according to some theories, the narrator of the game[[/note]], and at worst they're a [[ManipulativeBastard Manipulative Bastard-esque]] WoobieDestroyerOfWorlds who [[PlotTriggeringDeath kicked off the entire plot]] purely for revenge. Either way, if you encounter them at the end of the Genocide Run, it's pretty likely that [[HumanoidAbomination they've stopped being human entirely]] — and if the other characters' comments on how you look in their eyes through said run is any indication, ''so have you''.]]

** If you go in Sans' room, Papyrus will call him immature... right before asking Frisk if they've seen his action figures.

* IAteWhat: Plenty of the food items in the game are made of questionable ingredients. Hot dogs made of water sausages, burgers made of sequins and glue, steak made of anything but meat, junk food made of actual garbage...

* IGaveMyWord: In an optional conversation near the end of the Neutral run, [[spoiler:Sans says that if he hadn't promised Toriel he'd leave any humans he saw alive, the player would be "dead where [they] stand." It is also the reason why he first fights the player near the very end of the No Mercy run: He had been trying to honor his promise to Toriel for as long as he possibly could, even in spite of the death and horror the player was inflicting upon his friends, acquaintances, and even ''family'', but by the time you meet him before facing Asgore, he has realized that far too great things are at stake to allow a monster like the player to live. He pulls out ''all the stops'' to make sure that you don't get past him.]]
* ILoveTheDead: PlayedForLaughs during Mettaton's quiz. One of his questions is "Would you smooch a ghost?" and ALL the answers are "Heck Yeah!" This becomes more significant after you learn [[spoiler:Mettaton is probably Napstablook's cousin (thus, a ghost) in a robot body]].

** Twice. The first is in the neutral ending, during the boss fight against [[spoiler:Flowey]], as you Act to help the human souls break free of his control. The second is in the true pacifist ending, during the boss fight against [[spoiler:Asriel, as you Act to free the "Lost Souls" of your friends and calm down Asriel himself.]]
** Happens in the No Mercy run, with the final boss pleading for you (as in, [[TheFourthWallWillNotProtectYou you, the player]]) to remember your humanity and lay your weapons down. [[spoiler: Subverted in that, should you choose to spare him, [[SchmuckBait he traps you and destroys your soul, killing you.]] DoubleSubverted since the only remaining way to turn back on your evil ways at that point is to quit and start over. On the Game Over screen, Sans reiterates this by telling you "if we're really friends, you won't come back".]]

** The strongest piece of armor in the game which you actually '''do''' get to use is the Temmie Armor, and it is appropriately hard to get. First, you need to discover the secret Temmie Village. Then you need to buy the Temmie shopkeeper a college education (for 1000 gold). Only then will she sell you the armor... for 9999 gold! The price is reduced if you die a lot, but even after 23 deaths, it's still expensive at 750 gold.

** Muffet will let you go instantly if you eat the Spider Donut or Spider Cider during her fight, as it proves you ''did'' participate in her bake sale. Also, if you grind out the coins for it and buy one of the super-expensive items at the bake sale in Hotland, Muffet won't even take you into the battle system. She will also spare the player instantly [[spoiler:if they're on a ''Genocide'' Route, because despite all the murder you've committed, you haven't harmed a single spider.]]
** {{Downplayed|Trope}} in the True Pacifist final boss; [[spoiler:if you eat the Butterscotch Pie while trying to save Toriel and Asgore, you'll be a single act away from saving them both. In the same battle, saving one of them will instantly save the other even if you didn't act on the latter. The same holds true for Sans and Papyrus.]]

** [[EarnYourBadEnding Should you encounter them]], the [[spoiler: first Fallen Child]] will give you a short speech, then seemingly attack ''[[BreakingTheFourthWall the game itself,]]'' closing it almost instantly. When you reopen the game... [[WhamShot you are greeted by]] ''[[ApocalypseHow nothing at all.]]''

** In the normal route final battle, [[spoiler:Flowey taunts the player, challenging them to cry for help, for someone to save them, followed with "But nobody came". In the No Mercy Run, he himself describes this as his exact reaction upon first finding himself as a flower.]]
** On one of the tapes with [[spoiler:Dreemurr home videos, you can hear Asriel asking the First Child to "do their creepy face".]] In the No Mercy run he, [[spoiler:now in his Flowey form, eventually becomes terrified of you and angrily says: "S-s-stop making that creepy face! This isn't funny! You've got a SICK sense of humor!".]]
** At the end of the normal route, [[spoiler:Asgore introduces himself by saying, "Nice day today, huh? Birds are singing, flowers are blooming. Perfect weather for a game of catch..."]] At the end of the No Mercy route, [[spoiler:Sans echoes the line: "it's a beautiful day outside. birds are singing, flowers are blooming. on days like these, kids like you... '''Should be burning in hell.'''"]]

* {{Irony}}: A game that is heavily critical of replaying it makes it, by far, one of the most replayable games ever. One might ask, "What if I spare this boss?" "What if I spare that boss?" "What if I do a No Mercy run after a Pacifist run?" "What if I do two No Mercy runs?" "What if I do two pacifist runs?" etc, etc. Though given the game's overall message, this could be completely intentional by making you choose, honor Flowey's last request to let the happy ending be? Or reset everything to scratch the itch?

** Attacking a monster who doesn't want to keep fighting will always do massive amounts of damage; however depending on if you're doing a neutral or a full No Mercy run, it may be more or less effective than just killing the monster outright on the first turn. Papyrus will ''always'' spare you at most one turn before you deplete his HP, so there's no way to kill him without invoking this trope.

** In the Pacifist path [[spoiler:credits, the shot of Mt. Ebott is suddenly replaced by Asriel's powered-up form asking you if you thought it was ''really'' over. Subverted, as he then reverts to his non-powered "child" form (with a sheepish grin on his face) and he just wanted to tell you that you still need to watch the backer credits.]]
** If you [[spoiler:do a Pacifist run after a Genocide run, everything goes great until Toriel walks out of Frisk's room, at which point Frisk opens their eyes and reveals themself to still be Chara with a nightmarish smile and Flowey’s laugh]]. Unless you [[spoiler:choose not to stay with Toriel]]. Then, you [[spoiler:get the usual photo of everyone together... except Frisk has been replaced by Chara, and all of the other faces have been crossed out.]]

** Subverted when [[spoiler:Asgore asks Toriel if they can be this in the GoldenEnding. She responds with a blunt "no," though Alphys hopes they will reconcile.]]

* KilledMidSentence: [[spoiler:While mocking the player for falling for one of his tricks, Sans gets pretty much sliced in half and fatally wounded.]] Everything he knows [[spoiler:about the game's mechanics]] doesn't help him; since this is basically [[spoiler:''cheating the battle system'' by having the character attack twice during their turn]], he does not see it coming.

* KillOnSight: Asgore declared that any humans who appeared in the Underground are to be killed following [[spoiler:the death of his son at human hands]]. He regrets the decree immediately once he calms down, but by that point it's too late to rescind the order.

** In the fight with Asgore, you have to beat him to a near pulp to win because he destroys the Mercy button. Once that happens, he [[spoiler:confesses that he did wrong in restarting the war against humans, because it cost him his wife and he never got his son back. Then he tells you to take his soul and cross the barrier.]]

** The game offers you a meta one during the final cutscene of No Mercy, if you're observant -- [[spoiler:after the Fallen Child takes control and murders Asgore without your input, they'll turn on Flowey. When he reverts to Asriel's face and voice and begs not to be killed, the Fallen Child [[EvenEvilHasLovedOnes falters,]] and you have to push the button to make them kill their adoptive brother. Alternatively, you can hold ESC, quit the game, and SetRightWhatOnceWentWrong, but if you got ''that'' far without giving up, you probably won't do it now.]]

** Also, this is invoked by Sans when he [[spoiler:gives you a last chance to choose mercy during the fight with him... then kills you if you take it. From a certain perspective it's not even a subversion, since he specifically points out that your only option at this point to avoid a bad ending is to quit this playthrough entirely.]]

** The leitmotif that appears in "Once Upon a Time" appears to be the main leitmotif of the game. It appears in "Undertale", "Home", "Can You Really Call this a Hotel, I didn't Receive a Mint on my Pillow or Anything", "Hotel", [[spoiler:"Hopes and Dreams", "SAVE the World", “Reunited”, "Bring it in, Guys" and "Last Goodbye". It's often believed that this leitmotif is associated with either the first Fallen Child or Frisk.]]
** "Memory" appears in "Undertale", "Finale", and [[spoiler:"His Theme". It is associated with Asriel Dreemurr.]]

** [[spoiler:Undyne the Undying and Mettaton NEO's]] boss themes have extremely similar melodies; there are a few potential reasons for this, including it being [[spoiler:the standard 'Genocide' boss theme]] or it [[spoiler:being [[OmnicidalManiac the First Fallen Human's]] own fight theme.]]

** It's implied within the game files that "Determination" is meant to be [[spoiler:Asgore's]] theme alongside [[spoiler:"Bergentrückung" and “ASGORE”]].
** Finally, a particularly devastating one appears in [[spoiler:"Hopes and Dreams"]], which is shared with "Snowdin Town", "Shop", "Dating Start!" and "Dating Fight!" [[spoiler:The motif appears in the most lighthearted, welcoming and, to JRPG fans, most expected parts of the game -- in a populated town, in a shop, and while interacting with well-respected [=NPCs=]. So when the melody shows up in "Hopes and Dreams", during the final battle in the True Pacifist run, in which the villain has absorbed everyone that contributed to those earlier warm and fuzzy feelings and is using all of those characters' powers to boost his own strength, the emotional impact hits ''hard'' as the player realizes both the strength they're up against, and whom they are fighting for.]]

** This happens to "Your Best Nightmare" in [[spoiler:Flowey]]'s battle during the SOUL attacks, after you "call for help" via the Act button and before the bullets are replaced with healing items.]]

** [[spoiler: When Asriel came back to life]], he named himself (a sentient golden flower), [[FoulFlower FLOWEY.]] [[spoiler: It seems Asgore’s GiverOfLameNames trait runs in the family...]]

** This also comes into play in a No Mercy Run, [[spoiler:where you try to trick Monster Kid into turning around so you can get right into the fight with them and kill them before Undyne shows up. It doesn't work, and you still have to fight Undyne the Undying.]]
* LoopholeAbuse: A meta-example: if you [[spoiler:quit a No Mercy run by pressing ESC right before the Fallen Child kills Flowey and reset, you avoid the corrupted ending that comes from completing it. Flowey is an UngratefulBastard about it the next time you see him.]]

* MadeFromRealGirlScouts: Several times throughout the game, there are references to the spider bake sale. It seems innocuous enough. You put money in a web and spiders bring you a spider donut or some spider cider. However, one sign, encountered early on, makes it a little more unsettling- "Come eat food made by spiders, for spiders, of spiders." Buying the cider and deading its description tells you that it is "Made with whole spiders, not just the juice."

** Asriel Dreemurr. The obvious conclusion is that Dreemurr is an anagram of 'murderer', but [[spoiler:Azrael is the angel of death and renewal in the Bible, fitting quite well with Asriel's full powered persona as "The Absolute God of Hyperdeath" (meaning, perpetual death and instant renewal).]]

** Everyone in the game seems to display some level of this, all of them without ever ''quite'' BreakingTheFourthWall. They acknowledge that the player is a unique entity, but they always address the PlayerCharacter, not the player themself. [[spoiler:With one notable exception: after completing a True Pacifist run, upon re-opening the game Flowey will appear, saying that there is one last threat to everyone's happiness: you, the player. He pleads with the player to not reset and "let Frisk live their life," specifically differentiating between the PlayerCharacter and the player.]]

** You can't gain EXP by sparing enemies. You need to kill them if you want to increase your LV. (In the demo you can spare injured monsters for EXP; this ability was removed in the full release, however, as it [[spoiler:[[GameplayAndStorySegregation contradicts certain events late in the story.]]]])
** Particularly, a PacifistRun will not only net you a more positive ending but also reward you with bonus dialog on the credits screen.

** During the PlayableEpilogue during the GoldenEnding, [[spoiler:the main menu screen, which had been filling up with the characters you befriend over the course of the game, now has a lineup of all of them. There used to be a noticeable gap between Asgore and Monster Kid, with no way to get anyone else to join the lineup. However, as of the January 2016 patch, the gap is no longer there.]]

** Money's usefulness is heavily dependent on which route you're going: On a Pacifist run, it's borderline useless since the cheapest healing items heal more or less your entire health bar (especially the Bicicles from Snowdin, which are also double use). On a Neutral run, you might have more use for the high end healing items you can get in Hotland because of your increased health pool, but with high LV comes a lot of defense and battles end sooner so you're less likely to need them to start with. On a No Mercy run, it seems irrelevant since everyone's too terrified of you to do business, and even Temmie seems smart enough to instead try to scam you with useless stuff. [[spoiler:At the end of the No Mercy run, however, money is ''vital'', because Sans will quickly tear through you if you don't have food to help out. This may mean spending a lot of money on the expensive foods at Burgerpants' shop, even if you saved some of the better, limited ones like Toriel's pie and the Instant Noodles.]]
** From a technical standpoint, it's played completely straight. You can get infinite money ''halfway through the game'', and the method to do so isn't very subtle (though it's pretty tedious- repeatedly filling your inventory with Dog Residue, and selling it to Temmie). In fact, exploiting it is the only feasible way to get the best armor in the game.

** [[spoiler:Amid the horror of the Amalgamates and how they came to be, you can encounter the creepy-looking Endogeny... and it acts like a big, weird gelatinous dog. The unsettling Woofenstein plays during the fight, which is essentially just a rhythmic, hollow barking sound that slowly speeds up. After you appease it by playing fetch and petting it, it plays a modified Dogsong, one of the goofiest, most light-hearted songs in the game.]] A jarring shift of tone considering the rest of the place, but a much-needed one to keep it from being too heavy.

* MoreThanMindControl: Implied to be the case [[spoiler:with your friends when fighting the final boss of the true pacifist run, Asriel. The Lost Souls refer back to their motivations and negative emotions from earlier in the game; reminding them that Frisk cares for them helps them to break free.]]
* MortonsFork: Finish a Genocide Run, and [[spoiler:Chara will show up and offer you a chance to destroy the universe. Regardless of your answer, they kill you and do it anyway, crashing the game.]]

** Neutral: Basically the default ending, you get this if you don't qualify for the other two. First, you fight Asgore. [[spoiler:Then, you can kill him or spare him -- but if you spare him, Flowey kills him himself, and then shatters his SOUL either way so you can't use it to escape the barrier. Then he steals the human [=SOULs=] and goes OneWingedAngel to fight you as Photoshop Flowey -- unless you've gotten this ending before, in which case he figures, why bother?]] Either way, you end up outside the barrier, somehow, and much later, you receive [[https://pcy.ulyssis.be/undertale/endings.pdf a phone call]] from Sans.

*** Alphys ending: Abort a KillEmAll run by not depopulating the Hotlands + CORE area[[note]]The actual coded requirement is to kill Toriel, Papyrus, Undyne, and Mettaton, and have a "murder level" of at least 12. The [[https://www.reddit.com/r/Underminers/comments/3r1hcc/using_undertaleini_to_activate_flags_specifically/cwl1n4g?context=3 murder level calculation]] makes it clear that this is the only way to do that; specifically, murder level 12 is reached by killing Undyne the Undying, at which point the only ways back onto Neutral for this ending are to spare the Royal Guards 01 and 02, spare Muffet, or fail to exhaust the random encounters in Hotland and the CORE. In all cases, you will face Mettaton NEO, who cannot be spared.[[/note]]: [[spoiler:Sans hands the phone to Alphys, who declares she has to do ''something'' about your murder rampage, and for what she does (and a lack of better candidates) the monsters elect her as their new leader. She only called to tell you she hates you for what she did, and laments that she should have killed you when she had the chance.]]
*** "Dirty hacker", or "error handler": This ending [[DummiedOut can't actually be reached]]; every possible game state will somehow lead to another one. If you ''could'' reach it, Sans would admit that he has no clue how you did it, and suggest telling Toby how you got there -- but then admit you're probably only seeing it because you hacked the game.
** GoldenEnding, mostly known as "True Pacifist", though the naming screen EasterEgg indicates it was probably supposed to be something like "mercy run". After getting a Neutral ending and sparing Flowey, he'll give you a hint as to how to get here -- kill 0 enemies, and hang out with Papyrus, Undyne, and Alphys. You can't actually hang out with Alphys unless you've gotten a Neutral ending, which ensures that you can't get this ending first, but if you killed 0 enemies and gave Undyne the water, you won't have to reset, just reload. You go through the True Lab and learn of Alphys's failed experiments, and how Flowey came to be. Then, when you face Asgore, Toriel interrupts the fight and tells the two of you that there will be no killing today. All of your friends gather... putting them in place for the final boss to take advantage of them. [[spoiler:Flowey appears to steal all of their [=SOULs=]. With six human [=SOULs=], and the SOUL of every monster in the Underground making up for the seventh, Flowey can finally take on his true form -- Asriel Dreemurr. After an intense fight, you save all of your friends' souls, allow Asriel to make peace with himself and you, break the barrier on the underground, and live a life with all your friends, and every monster on the surface in harmony with humans. You either live with Toriel taking care of you, or remain in contact with her as friends.]] Arguably the true ending, as it's the only one with a credits sequence.

** Undyne treats her cooking lessons this way, showing you such tricks of the kitchen trade as pummeling vegetables with your fists and aggressively heating the stove to the point where [[LethalChef her house catches on fire]] - just for the sake of proving your [[HotBlooded FIERCE PASSION]]. This is all after Papyrus [[SuperWindowJump defenestrates himself]] from the room to "let the two of you get to know each other." Possibly served with some discourse about ice cream women in the human world terrorizing everybody with energy spears.

* MurderIsTheBestSolution: Flowey seems to think so, and advocates it. In gameplay, however, unless you're majorly overlevelled for the area you're in, most fights take just as long to kill someone than they do to spare them (about three to five turns, depending on the enemy setup), making killing, even in self defense, unjustified.

** The Mad Dummy uses an uptempo remix of Napstablook's battle music, "Ghost Fight", during their fight. [[spoiler: The Dummy is Napstablook's cousin]].
** "Finale", a song used while fighting the final boss of the Neutral route, has a part where "His Theme" is just barely audible. [[spoiler:This is a hint toward Flowey's origins as Asriel]].

** "ASGORE" has motifs from "Heartache" and "Determination", hinting that [[spoiler:Asgore has a connection to Toriel]] and [[spoiler:he's the one speaking on the Game Over screen]].

** Alphys makes it clear how much she regrets [[spoiler: the accidental creation of the Amalgamates]] and despises herself for doing it, but is also too terrified of what the rest of the kingdom would do if they ever found out about what she'd done. So instead she keeps it a secret, her guilt and self-loathing steadily growing the longer she hides the truth.

** [[spoiler:Flowey in his final form]] knows how to [[spoiler:SAVE]] and abuses this ability to land cheap shots after you dodge. Technically, this ''is'' following the same mechanics of the game, of which he has full knowledge, as you do. Where this trope comes into play is, in that you're limited to one [[spoiler:savefile. Photoshop Flowey has access to ''save states'', and no less than six slots. The closest thing to that on your side requires outright ''cheating'', by screwing with your save folder and/or backing up several old saves, which obviously cannot be done in normal gameplay.]]

** [[https://www.youtube.com/watch?v=NdS_rEzAFhc MeGaLoVania]], which was originally the final boss track for ''VideoGame/{{The Halloween Hack}}'', makes a reappearance as the theme for the final boss of the Genocide route. The song also appears in VideoGame/CognitiveDissonance[[note]]although this was a fan remix[[/note]] and in WebComic/{{Homestuck}} as something of a leitmotif for Vriska Serket. You can only hear the song by playing the game much like Vriska; killing your way through everything to max out your LV and ignoring what [=NPCs=] say.
** Like Dr. Andonuts from Fox's ''The Halloween Hack'', [[spoiler:Photoshop Flowey is an abomination that hijacks the game over screen if he happens to kill you. Both of them then laugh at your face endlessly, though whereas Andonuts required a manual reset, Flowey simply shuts the game down instead.]]
** [[spoiler: After Flowey hijacks the game in the neutral route]], the image that appears when the intro says "Long ago, two races ruled over the earth: HUMANS and MONSTERS" is changed to the version that appeared in the kickstarter demo, which had a Loox (aka the one that looks like [[WesternAnimation/MonstersInc Mike Wazowski]]) appear as the monster instead of the rabbit-looking one that shows up normally.

* NewGamePlus: The game keeps track of the player's activities which affects their experience during later playthroughs. Even if the player resets after reaching the end, certain things persist from their previous runs. Inverted in that only clearing the True Pacifist ending lets you do a "True Reset", which carries over nothing. [[spoiler:Unless you have reached a certain ending...]]

** Right before the final fight in the True Pacifist ending, Flowey tells you it's your fault that [[spoiler:he can reach his true form since your making friends with everyone empowered them to gather in one place to help you, allowing Flowey to steal all their souls in one fell swoop.]]

** Alphys' experiments involving [[spoiler: DETERMINATION led to the creation of Flowey, a being that had the "will to live" but no soul, and therefore no capacity for compassion or love.]]

** Papyrus, Undyne and Mettaton, the {{Arc Villain}}s of Snowdin, Waterfall and Hotland, respectively. Papyrus is ThePollyanna, and even if you lose to him in battle will always stop before killing you and instead capture you (which means putting you in an unlocked shed next to his house). Losing to him repeatedly will make him feel bad about fighting you, and allow you to pass by him peacefully- he is also the first character who can be befriended in the game, and you can do so in literally any playthrough as long as you don't kill him. In contrast Undyne is a JerkWithAHeartOfGold who ''loathes'' all humans and hunts you down all over Waterfall in an attempt to kill you and take your soul, and befriending her at all requires having never killed a single monster on that run. Mettaton is a egotistical preformer who, though treating you playfully throughout your journey through Hotland, still fully intends to kill you and take your soul, [[ShootTheDog but is doing it to prevent Asgore from using it to destroy all of humanity]] (and also so that he can become a big-shot star on the surface).

* NoHarmRequirement: ''Undertale'' gives players the option to do this on nearly every encounter in the game. It's considerably more difficult, since it turns even a random encounter into a puzzle boss and you don't gain more health since you don't get the necessary EXP from killing enemies. Following through to the end, however, unlocks the game's GoldenEnding.

** [[spoiler:Photoshop Flowey begins the typical game over dialogue in Asgore's voice... only to reveal it's really him, laughing about the nightmare you'll never wake up from. Then he closes the game.]]

* NoSidepathsNoExplorationNoFreedom: Looking from certain high vantage points of Snowdin and [[spoiler:New Home]] implies the Underground is actually ''enormous'', but most of your journey is through relatively small, narrow and entirely linear paths with the occasional tease of other walkways you can't reach (like the conveyor belts where you find the frying pan, or the echo flower across the rainy path you see Monster Kid look at in Waterfall).

** In a True Pacifist Run when [[spoiler:everyone in the cast meets at the barrier, Undyne and Alphys oblige Mettaton by almost kissing, which is interrupted by Toriel saying, "Not in front of the human!"]]

** You survive your fall into the Underground because a bed of golden flowers breaks your fall. Toriel takes care of the flowers for these reasons. [[spoiler:The first Fallen Child got injured when they fell, because the flowers hadn't even been planted yet.]]

** On the route for the TrueEnding, killing any monsters from the True Lab onwards, including the TrueFinalBoss, will ruin the point of it being a Pacifist run. The game still lets you try, however. Attacks will just miss, partially because you wouldn't have the will to kill anybody at this point, partially because said monsters are either phantom-like in nature or [[spoiler:a physical god]].

* NiceJobBreakingItHero: [[spoiler:Right before the final fight in the True Pacifist ending, Flowey tells you it's your fault he can reach his true form since your making friends with everyone empowered them to come help you, allowing Flowey to steal all their souls.]]

* MeaningfulName: Asriel Dreemurr. The obvious conclusion is that Dreemurr is an anagram of 'murderer', but [[spoiler:Azrael is the angel of death and renewal in the Bible, fitting quite well with Asriel's full powered persona as "The Absolute God of Hyperdeath" (meaning, perpetual death and instant renewal).]]

** [[spoiler:The player character's name is actually Frisk, and the character you named at the beginning is really the Fallen Child.]]
** [[spoiler:Flowey]]'s true name is [[spoiler:Asriel Dreemurr, making it clear he's Asgore's lost son and that he CameBackWrong after his death]].
* TheGlovesComeOff: [[spoiler:The final battle against Sans at the end of a Genocide run. The game makes it pretty clear that it is ''done'' [[SeriousBusiness fucking around]].]]

* KarmaMeter: [[spoiler:It is revealed near the end of the game that [[ExperiencePoints EXP]] actually stands for "Execution Points", and [[CharacterLevel LOVE]] stands for "Level Of Violence". These stats essentially act as the game's Meter.]]
%%[[spoiler:What the EXP system ''really'' is.]]

* LandOfFaerie: The Underground, which the Monsters were banished to from the rest of the world, filled to the brim with curiosities and oddities alike. All they need is someone to get them out, and that's where you come in. [[EverybodyLives One way]] or [[KillEmAll another.]]

%%* MohsScaleOfRockAndMetalHardness: Can range anywhere from 1 ("Undertale") to 6 ("Hopes And Dreams/SAVE The World").

* InfinityMinusOneSword: The Worn Dagger and the Heart Locket, which belonged to [[spoiler:Asriel]], are some of the strongest equipment in the game and the final pieces of equipment one can find on a normal or Pacifist run. They don't need to be bought, either, and are difficult to miss, ensuring the player at least has something for the end boss if they've been neglecting equipment thus far.

** On a No Mercy run, the [[InfinityMinusOneSword Infinity-1 Swords]] are replaced by the Real Knife and The Locket, [[spoiler:which belonged to Asriel's sibling, the Fallen Child]]. They increase your stats by 99, but by this point, there is only one enemy left, who's immune to their effects. The one time you really get to see the Real Knife's long-awaited power? [[spoiler:When the Fallen Child slashes '''the world''' for endless damage!]]

** [[EarnYourBadEnding should you encounter them, the [[spoiler: first Fallen Child]] will give you a short speech, then seemingly attack ''[[BreakingTheFourthWall the game itself,]]'' closing it almost instantly. When you reopen the game... [[WhamShot you are greeted by]] ''[[ApocalypseHow nothing at all.]]''

** [[spoiler:Napstablook's cousin uses a more uptempo remix of their theme, "Ghost Fight", during their boss battle.]]
** [[spoiler:Similarly, if you listen very, ''very'' carefully during, you can hear notes from "Ghost Fight" in Mettaton's "Metal Crusher" theme, hinting at Mettaton's origins.]]
** [[spoiler:"His Theme" can be faintly heard in "Finale."]]

** [[spoiler:Observant players may realize "The Power of NEO", a remix of "Battle Against A True Hero", is also shorter than the latter song, hinting at the fact that Mettaton NEO is faking his strength and that the battle is going to end in a single turn.]]
** [[spoiler:The song "ASGORE" includes lines from Heartache and Determination, hinting at the connection between Asgore and the identity of the one speaking on the Game Over screen.]]
** [[spoiler:Asriel's theme plays after you spare Asgore, right before Flowey murders the latter. This hints towards Flowey's true identity.]]

* NotSoDifferent:
** Toriel says this to you if you BackStab her after she lowers her guard. [[spoiler:In the demo, kill her three times and Flowey mockingly says you're like him. Kill all the monsters and he says it more respectfully.]]
** The opening intro leads you to believe that monsters and humans are totally different and the monsters are painted as the evil ones. Should you spare monsters and talk to various [=NPCs=], you can see that they aren't really that much different from humans in terms of what they celebrate, what their favorite hobbies are, and so on, but very few character actually mention the similarities. [[spoiler:Should you get the GoldenEnding, the trope is further expanded upon where humans and monsters are able to coexist with each other peacefully and very easily since they're very much alike.]]

* LowLevelRun: Enforced in the Pacifist route. Since the only way to gain EXP and LOVE is to kill enemies, you'll be stuck at level 1 for the entire game. [[spoiler:Which is for the best as "EXP" and "LOVE" stand for "[=EXecution Points=]" and "Level Of [=ViolencE=]", respectively.]]

* NintendoHard: Averted for most of the No Mercy run, since the constant killings have made you ridiculously overpowered, except in two cases: [[spoiler:Undyne the Undying, a surprisingly difficult boss who emerges after you've already one-shotted Undyne, and Sans, a surprise Marathon Boss who utterly ''destroys'' you over and over again, and who you literally stand no chance of beating without cheating the battle system.]]

* NotNowKiddo: On the Genocide Route, [[spoiler:Flowey realizes you're going to kill him, so he flees to warn Asgore about you. Unfortunately for both, Asgore responds by brushing him aside.]]