Tear Jerker: Undertale

"You laugh, and keep laughing. It's SO funny, you can't stop. Tears run down your face. ... What? You didn't do that?"


  • A monster's death has their body instantly turn into dust. Just imagine someone's best friend or loved one dying in their arms and then turning into dust, never to be held or touched in their final moments. Similar to people in real life, monsters spread the ashes of their fallen kin on the things they loved most when they were alive.
    • Alternatively: Imagine someone dying alone, and no one ever finds their body because there isn't a body to find. Your loved one goes out on an errand like any other day, or perhaps goes out on a job you know is risky. And you simply never see them again, alive or otherwise. Even if you go searching for them, all that remains is dust that can't indicate cause of death or possibly even identity, if you even notice any dust to begin with. It's unlikely you'll ever know for certain just what happened to your loved one.
      • This even gets somewhat lampshaded during some of the possible conversations in the Neutral Ending where Papyrus will question why Undyne/Alphys went "on vacation" without telling him or picking up the phone. A similar conversation happens with Mettaton explaining that he thoroughly looked for Alphys and couldn't find her.
    • It really puts a few scenes in perspective should one remember this fact. The tutu armor found in Waterfall is explicitly mentioned by the description and Papyrus as being "dusty", implying that its former owner might have killed at least one monster before they met their fate. And in New Home, going into the child's room and looking into Asriel's toybox has only a two word descriptor: "Dusty toys."
  • The monsters waiting for their time of salvation to come. Some are still holding onto that hope that their king had given them while others have either gotten used to life in the underground or have plain just given up of ever escaping. It doesn't help that King Asgore had gotten cold feet and couldn't go through with his plan of obtaining 7 human souls to destroy the barrier after already obtaining 6 souls, which only prolonged the suffering of his people. In fact, the way some monsters react to the player character with fear and anger when said protagonist is trying to reach Asgore only further cements how desperate they are in wanting to be free from their eternal prison. In any variant of the neutral ending, the player character manages to escape from the underground, but the barrier remains intact and causes the monsters to remain trapped forever. Depending on what kind of neutral ending you get, the monster populace can be thrown into further despair knowing that they will never leave the underground.

The Ruins

  • Toriel remarks how happy she is to finally have some company and even prepared a lot of things to do with you. It makes your decision to leave more bitter and even worse if you're on a No Mercy run.
  • The Boss Battle with Toriel at the end of the ruins is one pretty much any way you play it.
    • Killing Toriel in the "neutral" path has her Go Out with a Smile, telling you one more time to be good and how strong you've become.
    • If you insist on sparing Toriel, it'll take you a while before she can get over her loneliness, fear, and doubts to let you have your way. But not without a Final First Hug, after which she politely - but firmly - tells you not to come back.
      • Which can make a player feel horrible even on a Pacifist run, as she will just disappear and never even once pick up the phone until the Golden Ending where she gleefully enjoys sending you messages. Though the tearjerkiness kinda loses its impact if you find out that the annoying dog has her phone.
    • If you're going for the Kill 'em All route, it becomes a Single-Stroke Battle, and ends with Toriel gasping, "Y... you... really hate me that much...?"
    • Toriel's attacks can be tricky to avoid. But if your HP gets low, any subsequent attacks have the bullets actively avoiding your soul to the point that it's impossible for you to take any more damage. However, it is possible to kill yourself if you intentionally take enough hits before the current attack ends. The look of shock and horror on her face if you manage this will haunt your memories.
    • You can add insult to injury for Toriel. Pick the MERCY option up until the very last text before she ends the fight, and kill her just as she is opening her heart to you. The shock of the betrayal causes her to snap, and she dies with a wicked smile on her face, remarking how "you're just like the others". It's somehow even worse than her death on a No Mercy run.
    • Toriel's battle theme is called "Heartache", and it fits perfectly since you broke her heart before the fight. This becomes doubly heart-wrenching when you discover near the end of the game that she lost both her own child and her adopted child at the same time many years ago, along with seeing other human children getting killed when they also tried to return home. It's no surprise then that she tests you brutally to see if you are strong enough to survive on your own.


  • Killing Papyrus can be a heartrending introduction to the full game's path of No Mercy. Instead of fighting, he offers to become friends, reasoning that you are simply alone. You kill him with one shot. After that... he still believes in you. His final words are his telling you he knows you can be good if you try, before finally turning to dust.
    • If you kill Papyrus on Neutral and go back into Snowdin, the NPCs will remark that the atmosphere of the town feels "off" all of a sudden. Arguably the worst part is that the patrons of Grillby's will wonder why Sans hasn't come in for lunch yet, and the bear at the gift tree will say that a box for Papyrus has gone missing. Bear in mind that Sans is the only one who knows what happened at this point.
    • It's even worse when you realize that Pacifist!Undyne spoke the literal truth when she said he'd get ripped into little smiling shreds.
  • If you kill all the dogs except for Doggo, when you find him at Grillby's he's convinced that his friends are playing a trick on him by sitting still so he can't see them.
    "They must be here, playing a joke on me. I'll just wait until one of them admits it..."
    • If you kill all the dogs besides the Greater Dog, he will make this face instead when you talk to him.
    • Killing Dogaressa causes Dogamy to become depressed and pretty much lose the will to fight. The dog he uses in his attack patterns even becomes sad and launches a single half-hearted projectile that doesn't even reach your SOUL if you're standing still.
      • If you kill both of them, the bear at the tree will talk about the couple's Christmas tradition. One of them would give the other a bone and the other would act like it's the first gift they've ever received even though they get it every year. Papyrus would then come and demand his bone back. He'll then wonder where the two are...
    • Attacking the dogs causes them to whimper and whine like real dogs, which can quickly make one feel guilty and upset about their actions. Especially Lesser and Greater Dog, as they are the least anthropomorphized of the dogs.
  • Snowdrake's backstory. His remarks about his father when you laugh at his jokes are funny at first, but when you later talk to his father at the MTT resort it becomes tragic. It's even worse when you encounter his fused, corrupted mother in the pacifist route. Also you can apparently heckle him enough that he runs away crying. Luckily, he's reunited with his family at the end of the pacifist route!
    • If you kill Snowdrake in a neutral run, his father's dialogue will change to him frantically asking where his son is.
  • The note you can find in an abandoned store in the No Mercy route.
    "Please don't hurt my family."
  • A lighter Fridge Sadness than most things on here, but several dialogue lines from Papyrus make it clear that he's not just overconfident, he's lonely. He doesn't really have anyone other than Sans and Undyne (and you, later on) and the townspeople of Snowdin only vaguely know about him compared to his brother. The guy attempts to capture you and become popular but really he just wants friends.


  • If you kill Papyrus, Undyne will call you out for it. On top of that, it's the only situation in which she doesn't engage in a Hot-Blooded fight intro.
    Look. Papyrus didn't come to his meeting today.
    Say what you want about him. He's weird, he's naive, he's self absorbed... But Papyrus has NEVER missed a meeting. And no matter what time you call him on the phone... Night, day, afternoon, morning... He ALWAYS answers within the first two rings.
    But now he's gone. And his brother isn't around, either.
    ...What did you do to him? What did you DO TO HIM?
    Papyrus, who I have trained every day... Even though I KNOW he's too goofy to ever hurt anyone...
    Go ahead. Prepare however you want. But when you step forward... I will KILL you.
  • If you do not kill Papyrus, she will instead call you out specifically for Snowdrake, Shyren, and any of the dogs, should you have killed any of them.
  • Everything about Undyne is even worse if you're going for a No Mercy run. She takes an attack meant for the Monster Kid, and is mortally wounded...but her Heroic Willpower and desire to protect her friends and the rest of the world from you brings her back as Undyne the Undying. Although she's much more difficult to beat in a No Mercy run, it isn't impossible to kill her, and you will probably feel bad for doing so:
    Before fighting you: "This isn't just about monsters anymore, is it? If you get past me, you'll...You'll destroy them all, won't you?
    As she's dying: "If you...If you think I'm gonna give up hope, you're wrong. 'Cause I've...Got my friends behind me."
    • The true tearjerker for Undyne is the battle text that appears as her track, "Battle with a True Hero" begins to play: "*The heroine appears."
  • At least No Mercy!Undyne goes down swinging and grinning triumphantly, confident that she's bought time for her friends to prepare to stop you. Neutral Path!Undyne continues to fight even after her HP bar has been emptied, but each turn, her body continues to deteriorate and her attacks slow down until they reach a pitiful crawl. And oh lord, the music. If you've finished a True Pacifist run then you've heard this song before: spoiler:it's a slowed-down version of 'Don't Give Up', the song that plays after you've all been trapped and a glimmer of hope has appeared. She goes out desperately clinging to life, after reflecting on how she never confessed her feelings to Alphys. Many people agree that her death in the Neutral route is the sadder of the two, especially since you don't need to be playing as evil to get it — you might have felt justified in fighting her since she was trying to kill you, or you might have been stumped on how to get past her.
  • Compared to the friendly Snowdin, with their friendly if not quirky residents, Waterfall is barely populated and the creatures that reside there are quite melancholy, surrounded by reminders of their sad history. Echo flowers tell you the conversations of monsters who wish to see the surface. There are no stars underground, so they wish on the sparkling walls. You may suddenly realize that you are a young child who has become trapped under a mountain, fearfully hiding in swathes of tall grass away from a silent, armor clad monster who wants nothing more than to kill you. The one friend you make during this whole segment realizes that you're a human, and asks you to insult them so they can hate you. Eventually you fall down into the dump, wading through waist-high trash-filled water and attacked by an intangible enemy bent on revenge.
  • The backstory behind the statue that's involved with the piano puzzle. It's a memorial statue of Asriel, that used to be a part of the fountain at the MTT Resort, before being replaced by a statue of Mettaton. It's implied Mettaton was the one who got rid of Asriel's statue. When you give the statue an umbrella, shielding it from the rain, this song plays in a music box for that area.
  • On the No Mercy path, you still have the option to hum with Shyren - if only to kill her later. Doing so, the normal event of Sans selling tickets is replaced with him watching from a distance, unable to stop you from eventually killing her. Note that this will happen after killing Papyrus, which makes it even more harsh from his perspective.
    • He'll actually watch this fight from a distance any time Papyrus has been killed, whether you're on a No Mercy run or not, which is almost worse.
  • Everything about Shyren, really. She loves to sing, but refrains from doing so because she isn't very good at it (her description outright calls her 'tone-deaf'). She also hides herself in a corner due to her shame over her 'scary' face, and only turns around to give you a nervous smile once you hum to her. Her sister has "fallen down" and was injected with Determination, causing her to meld with an Aaron and a Moldbygg. On top of all that, she's apparently started taking singing lessons...only to potentially be killed by you.
  • Finding out about Mettaton's backstory makes the already pitiful Napstablook that much more tragic.
    "Sorry, Blooky. My dreams can't wait for anyone..."


  • Tsunderplane, of all things, gets a special death animation if you kill it.
    "B-but I never got to...!" *BOOM*
  • Alphys's backstory, revealed once you get to the True Lab. Apparently she was under so much pressure to get her Determination experiments right that she turned the bodies of dead monsters into living abominations fused together in agony. She had to lie to the families of these monsters and became so depressed over the situation that she shut herself in, lived in garbage, and was on the verge of suicide before meeting Undyne.
  • If you kill Mettaton on a Neutral run, his almost constant smile disappears and he concedes that you are indeed strong enough to defeat Asgore. He then tells you not to worry, that even though it looks like he's dying he's merely running out of batteries, and that Alphys can fix him. The saddest moment comes afterwards, where he tells you that although he might not have what it takes to be a star, he still got to perform for one human and thanks you with a sad smile on his face. When the game returns to the overworld, Mettaton's previously invincible rectangular body lies on its side, completely busted.
    • To make it even worse, the dialogue for the employees at the resort change if you do this. Most of them are worried that Mettaton hasn't shown up, with some having no idea what to do without him.
  • Alphys insisting that even if you had killed (or did kill) Mettaton, she could always rebuild him, becomes this once you know that she literally couldn't - she could only rebuild the shell that houses Mettaton, who is actually Napstablook's cousin and apparently an old friend of hers.
    • Napstablook is the one to call at the end of the fight, complimenting their cousin on the show. Mettaton realizes this and tries to tell them to wait, saying "Wat, Bl..." before the shy ghost hangs up, struggling to keep his cousin's call anonymous when referring to them afterwards.
    • After finding out Alphys was tricking you the whole time, it's easy to feel a sting of betrayal, but seeing her initial shock at the state Mettaton is in, and how worried she was that this ploy could have left Mettaton hurt or dead, is incredibly touching. You can't help feeling for her at that point.
  • Also, the encounter with Mettaton NEO on a No Mercy run. Mettaton has to know perfectly well that he's no match for you, and if you've played the normal route you know that the power consumption for that form is so high that he couldn't survive a serious fight anyway. But he fights you anyway and pretends to be strong to try and bluff you into faltering, because as he says, there are people he wants to protect.
  • If you call Papyrus (before befriending Undyne) while approaching the Core, he'll be visibly upset that you're so close to leaving the Underground for good. It's one of the few times his sunny disposition falters. If you call him after befriending Undyne, she will feel depressed.
    Undyne: What!? No, we just became friends!! You can't already be that close...
  • In the True Lab, one of the Amalgamations — the one who hides in the form of a fridge — can be identified as the Snowdrake enemy's mother, at least as the primary consciousness. It can barely make an effort to attack you. Joking with it causes her to remember a part of herself, and should you 'Laugh' at the joke you told afterwards you get this bit of dialogue.
    You laugh, and keep laughing. It's SO funny, you can't stop. Tears run down your face. ...what? You didn't do that?
    It's so cold.
    • When you first see her "snowy" mumblings, you may assume that she's talking about her home, Snowdin. However, speaking to a green Snowdrake on Snowdin road reveals that he and his friends live in the forest and eat the lunches their parents bring them, but mentions that they share their lunches with "Snowy" since his parents aren't around. In the midst of losing her mind to the sixteen other monsters, she still has enough consciousness to remember her son without having to be reminded of him, unlike the other amalgamates.
    • The Snowdrake amalgamate also has their own unique battle music, which is a broken version of the Snowdin Road theme that's been sporadically slowed down and sped up in random places. It fits the monster very well.
  • Another one of the Amalgamations, Lemon Bread, becomes this if you buy the 'Mystery Key' from Catty and Bratty and enter Napstablook's cousin's house. Its primary consciousness is Shyren's sister, who had "fallen down" and contributed to Shyren's timid personality. When it speaks, the words fill up the screen in many separate text boxes, saying things like "Welcome to my special hell" and "But nobody came". It can hardly move, and you spare it by singing Shyren's song, reminding her of her sister.
  • Mettaton's death scene is as tragic as Undyne's was. First he tells you that Alphys can just repair him to make you feel better (a transparent lie that's not even consistent with the transparent lie that she uses). But then he tells you that even though he never got to go to the surface, he's happy that he at least got to perform for one human. He then dies, smiling.
  • So Sorry's self deprecation and death can be depressing.
  • Killing Muffet. After she dies, a tiny spider wanders to where she was, before scuttling off screen. It then comes back holding a rose, and slowly and gently places it down on the spot where she died before leaving the screen. It's as heartbreaking as it sounds.
  • If you want to be really monstrous, you can let the two Royal Guards get together during the fight, and then kill them. Watching the survivor's reaction after the first one dies will make you feel completely awful.
    • Killing 01 first only results in 02 saying "...! You!" but if you kill 02 first...
    "02... I never got to tell him"
    "01 is holding his head in his hands"
  • Once you're on the Genocide Route, the music in all major areas past the Ruins, as well as some other themes, will be slowed down. Whilst for the most part it creates a decidedly creepy atmosphere, the songs for Hotland and the Core instead sound hauntingly tragic. Bonus points to the latter for playing over the battle music as you kill the last random encounter monsters in the game.

Final Area

  • Walking through Asgore's home. It looks exactly like Toriel's. Heartbreakingly beautiful music plays, occasionally monsters will appear to tell you of his history. In his kitchen, there's a trashcan full of Butterscotch-cinnamon pie recipes. In Asgore's room, you can find a Santa outfit in his closet, and he has a trophy in the corner— Number 1 nose-nuzzle champs '98!. Also, you can find macaroni art for "King Dad" and a cup that parodies #1 Dad cups." If you've been playing a Pacifist run, you can find a locket in a room with the description "Best Friends Forever" and checking the mirror gives the description "Despite everything, it's still you."
    • As you wander through the house in the end of a Pacifist run, you begin to encounter monsters. They begin to tell you about how long ago, a human fell down and was adopted by the king and queen, and raised as their own alongside their real son. One day, the human child fell sick and died, their last request being to see the yellow flowers in their village again. The monster child absorbed their soul and took them back... only to be attacked by the humans in the village. He refused to fight back, and walked back home, still holding his sibling, and died as soon as he got to the throne room. The king, in his wild grief, declared war on humans and would destroy the barriers, murdering any human that came through. The monsters then describe how Asgore has given them hope again, and with the fact that a human is passing through the Underground, it won't be long before they're free again.
    Pyrope: You should be smiling.
    Vulkin: Aren't you excited? Aren't you happy?
    Froggit: You're going to be free.
  • It's hard not to feel bad about Asgore once you learn everything that happened to him. He lost his two children in the same night and on a grief-driven fit of anger declared war on humanity and that he'd use their souls to break the barrier and kill them all... Then he calms down and finds out he actually doesn't have the heart to bring his plans to come to fruition, and Toriel leaves him. He can't even back out of his plan because it's the only thing that keeps his people hopeful that one day their torment will end.
  • The fight with Asgore in the Neutral path. He starts by offering you a sad smile and saying it was nice to meet you. Then he averts his gaze and destroys the Mercy option so that you cannot spare him. Throughout the fight, he refuses to make eye contact with you. However, you can still talk to him, and he will react to it, ultimately lowering his attack and defense, which shows that he actually doesn't want to harm you, but feels that there's no other way. If you bring Toriel's pie all the way to this fight and use it, the smell will remind him of Toriel, further reducing his attack and defense. The theme music that plays during the fight, "ASGORE", combines powerful orchestral segments with parts that sound melancholic and desperate, adding to the tragic atmosphere of the scene. And when you finally defeat Asgore, the Mercy command gets rebuilt, and choosing it makes Asgore talk about how you could all be happy together, giving a glimmer of hope... Which is immediately and mercilessly stomped on by Flowey, who attacks Asgore by surprise, either killing him and destroying his soul or destroying what's left of him if you don't choose mercy.
    • Possibly even worse if this is another playthrough, and in the last one you killed Flowey. He'll still give that same glimmer of hope... but he'll dismiss it, saying it's just impossible at this point. And then he'll force you to take his soul by killing himself And then Flowey destroys his soul..
    • The lead-up to that fight as well, Asgore is nervous and heartbroken at the prospect of having to kill a child on his own. He spends the entire walk up to the final area doing his best to comfort a child on their way to their own execution (even making awkward small talk), trying to help the child cope with impending death in terms they can understand like being nervous about going to the dentist. At the end, he patiently waits until you are ready to get it over with. During the fight itself, he outright states that he doesn't care at all about power or revenge — he just wants his wife and son back.
    Asgore: ...I so badly want to say "Would you like a cup of tea?" but... you know how it is. Are you ready? If you are not, I understand. I'm not ready either...
    • "You tell ASGORE that he's killed you [X number of times] already. He nods sadly."
      • Then as you keep restarting the fight, the last sentence will change to "He nods grievously." and finally "He nods pitifully."
      • It gets even worse if you realize he's probably had to hear something like that nearly six times already.
      • Not sure if this is better or worse, but it's implied that none of the other six children actually made it to Asgore. You're the first he's actually had to confront.
    • "You tell ASGORE that you don't want to fight him. His breathing gets funny for a moment."
    • Say you want to go back when he offers you the last chance to turn back. "I see. Anything you want to do is important enough. Even something as small as reading a book, or taking a walk... Please take your time." Asgore really, really does not want to fight you.
  • The Battle with Sans on the No Mercy path. After a long hard grueling battle, Sans realizes he can't beat you, so he simply does nothing but never use his turn. But then if you wait long enough, he falls asleep. The Player can then move the entire box over to the fight menu to finish him off, where he will cough up blood (or ketchup?) and saunter offscreen before asking his dead brother if he wanted anything to eat before dying offscreen.
    welp. i'm going to grillby's.
    papyrus, you want anything?
    Sans: If we're really friends...You won't come back.
    • It's a small one, look at Sans' eyes while he says these lines. He looks so anguished it's impossible not to feel bad for him.
    Sans: you can't understand how this feels... knowing that one day, without any warning, it's all going to be reset.
    • The words themselves are bad enough, but it gets worse when you look at their meaning. Sans is the only player other than the human child who is fully aware of the resetting timelines. It's ambiguous how much he remembers from previous playthroughs, but if he's anything like the other monsters, he must remember something. That means that Sans has seen his brother killed over and over again. Every reset, he wonders whether Papyrus, whom he loves very deeply, will live to the end.
  • After dying and restarting his fight a certain number of times, what he says when you choose to attack after he once again offers to spare you is nothing but tragic.
    Sans: woah, you look REALLY pissed off. hehehe...did i getcha? well, if you came back anyway, i guess that means we never really WERE friends, huh? heh. don't tell that to the other sans-es, ok?
  • Talking with Sans in the neutral route after you've killed Papyrus can also be massively heart-wrenching. Regardless of how you answer his question, it's still painful.
    Sans: if you have some sort of special power... isn't it your responsibility to do the right thing?
    Answer yes: "ah. i see. ... Then why'd you kill my brother?"
    Answer no: "heh. well, that's your viewpoint. i won't judge you for it. ... You dirty brother killer."
  • One more note on the fight, Sans at the midpoint will say that somewhere, inside the player character, is the "memory of someone who wanted to do the right thing"...and pleads for them to remember him and abandon this. He knows about the "anomaly" (IE you), and he can see Chara/The Fallen Child in front of him. He's not talking about either of you. He's calling out to Frisk.
    please, if you're listening... let's forget all this, ok?


  • The final boss battle... the TRUE final boss battle. Once you understand Flowey's true nature.
    • The Wham Line is this, after you've learned exactly who the final boss was in the True Lab.
    • It's clear that Asriel's form is based entirely on that character's idea of the Rule of Cool. Which means that what that character loves is rainbows, stars, and his mom. Even after everything he's been through, he's still just a little kid.
    • Falling in battle. ...But it refused. Death Is a Slap on the Wrist indeed.
    • To weaken the boss, you call out to and SAVE all of your friends, who don't remember you and attack you. When they realize who you are, they start cheering you on and promise to remain friends forever.
    • The saddest part of the above is that most of your friends simply revert to the negative feelings they had over the course of the game. However, Sans instead begins saying things like "just give up, i did" and "why even try", in shaky text, devoid of Comic Sans MS. It comes completely out of the blue and is one of the only major hints to Sans's existential depression in a non-No Mercy run. What's more, when he's saved, he doesn't even really take it back, unlike everyone else, he simply says he's "rooting for you".
    • The final sequence as Frisk reaches out to SAVE Asriel over and over, despite Asriel's protests and confusion.
    Huh? What are you doing...? Wh... what did you do...? What's this feeling...? What's happening to me? No! NO! I don't need ANYONE! STOP IT! Get away from me! Do you hear me!? I'll tear you apart!
    ... Chara... Do you know why I'm doing this...? Why I keep fighting to keep you around...? I'm doing this... Because you're special, Chara. You're the only one that understands me. You're the only one who's any fun to play with anymore.
    ... No... That's not JUST it. I... I... I'm doing this because I care about you, Chara! I care about you more than anybody else! I'm not ready for this to end. I'm not ready for you to leave. I'm not ready to say goodbye to someone like you again...
    So, please... STOP doing this... AND JUST LET ME WIN!!! STOP IT! STOP IT NOW!!!
    ... Chara... I'm so alone, Chara... I'm so afraid, Chara... Chara, I... I...
    • As the fight progresses, Asriel begs you to let him win so you never leave, and he doesn't have to be alone.
    • The Call Back to the first boss as Asriel's attacks start avoiding you, just like Toriel's. Even when he begins screaming and firing an unavoidable attack, he lowers your health to a miniscule fraction but can't kill you.
    • Asriel saying that when he releases everyone's SOULs, he'll go back to being Flowey. And he does it anyways. This is doubly heart wrenching since he says that he doesn't want his parents to see him as he is now since it would break their hearts once more. He insists going back as Flowey without his parents knowing is better that way.
    • Asriel breaking down and crying, and being comforted by Frisk.
    • Choose comfort and prepare for the most heartrending line of the entire game. "I don't want to let go..."
  • The final walk on the True Ending. Seeing everyone be happy and eager to explore the surface at long last.
    • If you take the time to backtrack... You meet Asriel where you originally fell down. He's remorseful, but happy you took the time to come visit him.
      • "You can't regret hard choices your whole life, right? Well, not that I have much of a life left. But that's beside the point."
    • If you did have a last talk with Asriel, he'll warn you not to trust him once he transforms back into Flowey. And so, once you open the game again, Flowey greets you. What does he have to say? He begs you and the Fallen Child to leave everyone in peace and not reset the timeline, that's what. And if you do want to, he asks to at least make it so even he wouldn't remember everything that happened.
      • Flowey: So, please. Just let them go. Let Frisk be happy. Let Frisk live their life.
    • An easily missed bit of fluff, but speaking to the turtle shopkeeper has him reveal that Asgore and Toriel are a special type of monster that can't grow old unless they have a child. When the player character asks if they would work as a surrogate child, the shopkeeper scoffs and assures them "If you were Asgore's child, he'd certainly outlive you." It puts a sombering twist on what seemed like a perfect ending.
    • Throughout the game, the major characters you meet and befriend start to appear on your save screen whenever you start up the game, as the theme gets more instruments the further into the game you are. And then the True Ending completely empties them all out and replaces the theme with a low, more hollow and ambient tone. Your hope and determination let all the monsters leave the underground, but now it's a dull void, almost as if trying to scratch your itch to reset everyone's happiness so you can play through one more time.
      • If you do continue after the true ending, you can see everyone...except Asriel. He'll be gone.
  • The No Mercy Path ending. Where to start?... After killing every possible enemy and Boss in the game, including the aforementioned and ultra-difficult Sans battle, Asgore is seen talking to a crying Flowey before greeting you. You're so far gone at this point, Asgore doesn't even realize you are human. You immediately start a fight with him, despite him wanting to resolve things peacefully, and cut him down before Flowey finishes him off out of desperation to please you. Once he sees you're unimpressed, he begs for his life before being butchered to pieces. Chara then turns towards you, congratulating you for your hard work, before erasing the entire game world, leaving an empty void where there used to be The Friendly RPG Where No One Has to Die.
    • Flowey's brutal death is even worse if you know his true identity. In fact, when Flowey tearfully begs you not to kill him, Flowey's Voice Grunting and face changes to Asriel's right before you kill him. If you're doing a No Mercy run after having completed a pacifist run, where Asriel's character is explained, expect to feel nothing but misery.
    • Even the last-second stop of No Mercy is a bit heartwrenching. You try to avoid killing Mettatron NEO, and in his last moments, he realizes you were motivated either by fear of monsters or simply didn't have enough hatred to be utterly evil. This one good-ish action results in Dr. Alphys surviving to become the new Queen...and she's in a complete Heroic BSOD, cursing her cowardice for not killing you when she had the chance and mourning her friends.
  • After you finish the game for the first time, Sans calls you on your cell phone to tell you how the underground is doing. The contents of this call change depending on who you've killed during the game (if anyone). And if you were evil enough to kill Papyrus, this is what he says:
    Sans: Sometimes the queen talks about... how she'd like to see you again. Isn't that nice? ...I don't have the heart to tell her what you did. Do you know how she'd react? If I told her that 'cause she protected you... you went on to kill my brother...? Anyway, never come back here. You are not welcome.
  • If you kill all the bosses, Sans' call is very creepy. If you only spare Undyne, that's the only one where Sans addresses the possibility that you killed Toriel.
    Sans: Or maybe she's not feeling anything at all...? You'd better watch yourself, kid. Things are lookin real bad for you.
  • On the Neutral path ending, after you've defeated God Flowey and if you decide to spare him, he repeatedly tells you that he hasn't changed or learned anything, and he'll keep coming back and keep killing. If you continue to spare him, he starts to break down and cry and says this:
    Flowey: ...why? Why are you being... so nice to me? I can't understand. I can't understand! I just can't understand...
    • This moment becomes even sadder after you learn exactly what Flowey is. As a creature with no soul, he is literally unable to understand compassion and love, and he’s self-aware about it. In the no mercy run, he even tells the player that he tried in several other timelines to love again, but he was incapable every time. His breakdown becomes even harsher in hindsight with that information.
  • If you kill every boss except Papyrus, he leads the underground since there was nobody left to lead, but he laments that he misses his friends. Papyrus is innocent enough to believe that Undyne and the others were on an extremely long vacation.
  • It's possible for Mettaton to take the throne if nobody is left to do so. Though his dialogue is mostly lighthearted, he starts to break character when he mentions some of the kingdom's problems. Finally, he regrets how he treated Alphys, and laments not being able to find her to apologize and ask her to rule with him. He ended up creating a statue of her in her memory.
  • In one ending, Undyne falls into depression after Asgore and Alphys both vanish. She loses her friends, job, and home, having to live with Sans and Papyrus. She becomes miserable, and doesn't even want to plot revenge on you, saying it "won't bring anybody back". Papyrus then pleads that you bring them back, for Undyne's sake.
  • If you kill everyone (but don't go far enough to trigger the No Mercy path), the Underground falls into chaos as everyone gives up hope.
  • In the endings where Toriel survives but Undyne doesn't, she takes over and tries to enact a policy in which humans that end up in the Underground are treated as friends. Nobody is in favor of this, and she ends up having to resign from her position to stop a coup d'état and returns to the Ruins with Sans while the Underground falls into anarchy. Sans mentions that Toriel still wants to see you again, but Sans doesn't have the heart to tell her what you've done after she let you leave the Ruins alive.
    • Alternatively, if you kill everyone except Toriel and Undyne, the same set up happens, except Undyne is spearheading the rebellion and banishes Toriel back to the Ruins before assuming the throne herself, more driven to destroy humanity than Asgore was.
  • What little information about Sans' backstory the player gets. For whatever reason, he's aware of what the player and Flowey are doing to the timeline, but lacks the ability to Save. Meaning he's lived through countless repeating timelines where his actions ultimately amount to nothing (even helping getting the monsters to the surface, only for all their hopes and dreams to get ripped away from them in another iteration of the "Groundhog Day" Loop). The reason he's so lazy is that he's simply given up trying (though he admits it could just be an excuse for his pre-existing laziness).
    • Everything Sans reveals about himself during the final battle with him is a pure, unadulterated marriage between Fridge Horror and Tear Jerker: imagine having to live with the knowledge that the universe you exist in can be manipulated on a whim by a God-like, all-powerful being who treats you like their toy. Imagine this being has the ability to either bless you with the perfect happy ending or brutally kill you and everything you love, not out of any desire for good or evil, but just because they're bored. Now imagine that being has the ability to reset the timeline you live in and erase all but the faintest memories of both these things; you know you're missing something, but can never fully grasp what it is, just that it was taken from you as easily as it was given. Imagine gradually losing hope at trying to fight this power, until eventually you've been run into such a state of nihilism you have no choice but to force a joke and a smile everywhere you go just to make it through the day. Imagine never being able to confide in anybody about this because doing so would either mean burdening them with the same existential nightmare, or being treated as if you've lost your mind. Imagine living with the knowledge that your beloved little brother, the one thing in your life that truly makes you happy anymore, is at the mercy of this being every time the world is reset. Imagine not even being able to fully numb yourself to the repeated anguish of his death, because you can never quite remember enough each time it happens. Now, as a cherry on top of all this misery, imagine that your only possible means of escape are entirely in the hands of this hedonistic god. If they don't feel like letting you keep your happy ending, nothing can let you leave, not even the cold embrace of death. Every time your heart stops beating, you suddenly find yourself back thrust back to the beginning of it all, struggling to remember whatever it was that just happened. Sans' life is a living Hell, and if he never manages to get out of it, there's nobody to blame but you.
    • It's also implied (though never explicitly stated) that he might just know something about Gaster, and is the only one who still does — the reason he's so prone to napping is that he's trying to repair the mysterious 'broken machine' that might've had something to do with Gaster's disappearance, along with all the other people who were Dummied Out. He might very well be working harder than anyone else in the Underground, and no one knows it.
      • On that note, Toby has said on Twitter that "you've all seen the happiest outcome. Neither of them" - i.e., Sans and either Gaster or Alphys — "could fix the machine, no matter how hard they tried. No one can."
      • In the new update, the room with the machine now has a secret action when you check the blueprint. There is a picture with three people, one presumably sans, with the other two assumed to be either Gaster or Alphys and they're smiling at the camera but what seals it is the writing on the picture Which is "dont forget" written in sans' text. This could possibly be a reminder to the other 'sanses' not to forget Gaster.
    • Sans' secret sort-of theme, It's Raining Somewhere Else, which plays on his 'date' with you, and later a slowed down version plays in his secret room with the broken machine. The first part is a slow, sad piano piece over the soft sounds of rain and what sounds like the background noise of a city, whilst the latter part is a more emotional, melancholy version of 'sans.', his usual quirky, comical theme. It makes for one of the more heartwrenching pieces in the soundtrack. Alongside the photo album Frisk can find in Sans' lab with a picture of Sans and a bunch of people Frisk doesn't recognize, it makes for a very bittersweet, nostalgic atmosphere.
  • The tale of Dr. Gaster in general, when it isn't straight up horrifying. Imagine, if you will, that you're suddenly ripped from your world in such a way that absolutely no record of you exists anymore. Then imagine that you're still able to see that your world progresses on despite that, meaning that your life had no value. And as stated above, there's no way to bring him back permanently; the only way you can even know about him is by messing around in the files. Dr. Gaster has it bad.
  • In the True Pacifist ending, if you go back to the place where you started, you'll meet Asriel in his true, child, form. He knows very well the atrocities he committed as Flowey and that he'll eventually regress into that form again. The worst thing about it is when he talks he can't even meet his mother and father, Toriel and Asgore, because he doesn't want them to suffer more.
    • The most tragic and heartrending fact, however, is that you cannot save Asriel. He is the only one which you cannot save from his fate. You are not given the option to offer your own soul to grant Asriel a happy ending.
  • If you kill anyone after befriending Undyne, it will lead to Papyrus delivering quite possibly his most heart-wrenching line in the entire game.

Meta / Non-canon

  • An AU No Mercy run with Papyrus as the final boss.
    • "From that one AU where Papyrus and Sans switch places. As exhausted as he’d be at this point, Papyrus would never fall asleep in a battle. There’d have to be some other way to incapacitate him."
    Papyrus: AND, AAND EV— AND EVER.. *breaks down*
    * Papyrus breaks down with grief.
    * He barely seems to know you're there.
    * All he does is sob.
    * [♥ FIGHT]
  • As a follow up, Genocide-Papyrus is a voiced over speech of Papyrus confronting you on the situation.
  • Fade Away will make you cry for Asriel if you didn't before.
    • And if that didn't, this will.
  • This comic of Frisk and Sans walking along until Sans comes across something that gives him a flashback to an alternate timeline where he had to kill Frisk.