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* SmugSuper: Sans definitely doesn't understate his own power when pushed far enough to use it. [[spoiler: In the No Mercy run, if the player loses to him (and they will - a LOT), he'll keep rubbing it in their face the first twelve times after reloading a save. Afterwards, he'll ditch the showing-off, and go straight into obliteration mode.]]
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* SmugSuper: Sans definitely doesn't understate his own power when pushed far enough to use it. [[spoiler: In the No Mercy run, if the player loses to him (and they will - a LOT), he'll keep rubbing it in their face the first twelve times after reloading a save. Afterwards, he'll ditch the showing-off, and [[NoNonsenseNemesis go straight into obliteration mode.]] ]]]]
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* DidYouActuallyBelieve: [[spoiler: HeroAntagonist example. He asks if the player really thought he'd just stand still after dodging their first attack. Subverted for the finishing blow, where immediately wakes up and sidesteps the first attack, before the second hit connects.]]
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* IronicEcho: [[spoiler:Papyrus insists, in a Genocide playthrough, that anyone can be a good person if they try. Before fighting Sans, he asks you if you think "anyone can be a good person if they just try" before asking if you wanna have a bad time.]]
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* IronicEcho: IronicEcho:
** [[spoiler:Papyrus insists, in a Genocide playthrough, that anyone can be a good person if they try. Before fighting Sans, he asks you if you think "anyone can be a good person if they just try" before asking if you wanna have a bad time.]]]]
** Also, if the player attempts a No Mercy run after doing Neutral or Pacifist, Sans echos something that [[spoiler: Asgore]] said previously when they met the protagonist, but of course with a different meaning.
--> '''Sans:''' it's a beautiful day outside. birds are singing, flowers are blooming. on days like these, kids like you...[[spoiler: '''Should be burning in hell.''']]
** [[spoiler:Papyrus insists, in a Genocide playthrough, that anyone can be a good person if they try. Before fighting Sans, he asks you if you think "anyone can be a good person if they just try" before asking if you wanna have a bad time.
** Also, if the player attempts a No Mercy run after doing Neutral or Pacifist, Sans echos something that [[spoiler: Asgore]] said previously when they met the protagonist, but of course with a different meaning.
--> '''Sans:''' it's a beautiful day outside. birds are singing, flowers are blooming. on days like these, kids like you...[[spoiler: '''Should be burning in hell.''']]
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* UpToEleven: [[spoiler: If you died from him for more than 11 times in a row, he stops counting how many times you died.]]
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i dont really think that's that trope.
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* {{Adorkable}}: Nowhere near to his brother's extent, but it's there, such as when he takes the player to Grillby's on a Neutral/Pacifist one and whilst making small talk with them, pulls out a comb and ''tries to comb his skull'' with it.
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* {{Adorkable}}: Nowhere near to his brother's extent, but it's there, such as when he takes the player to Grillby's on a Neutral/Pacifist one and whilst making small talk with them, pulls out a comb and ''tries to comb his skull'' with it.
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i'm sorry for this, my computer is having problems, ups.
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* ConditionedToAcceptHorror: [[spoiler: There is nothing he can do to stop resets so he stopped caring about going back in time or seeing surface. Unless a Genocide run is evoked, he just shrugs and only mocks the player for their kill count, knowing that it'll be reset anyway. And when the end of the world is confirmed upon his death, his reaction doesn't go much more than a simple "welp. guess that's it then."]]
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* ConditionedToAcceptHorror: [[spoiler: There is nothing he can do to stop resets so he stopped caring about going back in time or seeing surface. Unless a Genocide run is evoked, he just shrugs and only mocks the player for their kill count, count ([[LivingEmotionalCrutch that may or not include his own brother]]), knowing that it'll be reset anyway. And when the end of the world is confirmed upon his death, his reaction doesn't go much more than a simple "welp. guess that's it then."]]
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I had to open the "horror" part of it.
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* ConditionedToAcceptHorror: [[spoiler: There is nothing he can do to stop resets so he stopped caring about going back in time or seeing surface. Even when end of the world is confirmed upon his death, his reaction doesn't go much more than a simple "welp. guess that's it then."]]
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* ConditionedToAcceptHorror: [[spoiler: There is nothing he can do to stop resets so he stopped caring about going back in time or seeing surface. Even Unless a Genocide run is evoked, he just shrugs and only mocks the player for their kill count, knowing that it'll be reset anyway. And when the end of the world is confirmed upon his death, his reaction doesn't go much more than a simple "welp. guess that's it then."]]
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* ConditionedToAcceptHorror: [[spoiler: There is nothing he can do to stop resets so he stopped caring about going back in time or seeing surface. Even when end of the world is confirmed upon his death, his reaction doesn't go much more than a simple "welp. guess that's it then."
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* ConditionedToAcceptHorror: [[spoiler: There is nothing he can do to stop resets so he stopped caring about going back in time or seeing surface. Even when end of the world is confirmed upon his death, his reaction doesn't go much more than a simple "welp. guess that's it then." "]]
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* GroundHogPeggySue: Sans is an odd case;[[spoiler: he's aware of being stuck in a time loop and is very alerted when a reset happens, but he carries over little to no memories of previous timelines to present day. During Pacifist run, all he can do is to play the role of funny PungeonMaster so you could have a fun experience with the game and stop the resets for good once you reach the GoldenEnding.[[ThatOneBoss If you decide for a Genocide run however...]] ]]
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* GroundHogPeggySue: Sans is an odd case;[[spoiler: he's aware of being stuck in a time loop and is very alerted when a reset happens, but he carries over little to no memories of previous timelines to present day. During Pacifist run, all he can do is to play the role of funny PungeonMaster so you could have a fun experience with the game and stop the resets for good once you reach the GoldenEnding. [[ThatOneBoss If you decide for a Genocide run however...]] ]]
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* ConditionedToAcceptHorror: [[spoiler: There is nothing he can do to stop resets so he stopped caring about going back in time or seeing surface. Even when end of the world is confirmed upon his death, his reaction doesn't go much more than a simple "welp. guess that's it then."
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* DeterminedDefeatist: When he decides to step in and take action [[spoiler: at the end of Genocide run, he’s pretty much resigned to [[HopelessBossFight his tragic fate]]. But knowing that you’re about to destroy the world...he just can’t afford to not care anymore. He gives the player one hell of a final fight with the hopes of anomaly (the player) to RageQuit but at the end of the day, you are too [[SaveScumming determined]] to give up and he knows it from beginning to end.]]
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* DeterminedDefeatist: When he decides to step in and take action [[spoiler: at the end of Genocide run, he’s pretty much resigned to [[HopelessBossFight his tragic fate]]. But knowing that you’re about to destroy the world...he just can’t afford to not care anymore. He gives the player one hell of a final fight with the hopes of anomaly (the player) to RageQuit but at the end of the day, you are too [[SaveScumming determined]] to give up and there is nothing he knows it from beginning can do to end.stop you.]]
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There probably shouldn't be all these spoilers on a character page, but let's add an extra warning now that Sans has his ownpage.
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'''NOTE:''' As a main character, this page has the potential to give away '''major''' spoilers. Proceed with caution if you have not finished the game... you wouldn't want to have a bad time, now would you?
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* GroundHogPeggySue: Sans is an odd case;[[spoiler: he's aware of being stuck in a time loop and is very alerted when a reset happens, but he carries over little to no memories of previous timelines to present day. During Pacifist run, all he can do is to play the role of funny PungeonMaster so you could have a fun experience with the game and stop the resets for good once you reach the GoldenEnding.[[ThatOneBoss If you decide for a Genocide run however...]] ]]
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This is fair, right?
* AmbiguouslyHuman: Ambiguously ''monster'', in this case. You're normally given no reason to question him, considering he lives among [[FantasyKitchenSink far more bizarre creatures]] that are still clearly monsters, but what we learn about him [[spoiler:at the end of a genocide route]] is another matter entirely. [[spoiler:Not only is he ''[[ThatOneBoss unbelievably]]'' [[ThatOneBoss powerful]] - so much so that he makes Asgore, the millennia-year-old king of all monsters, look like a joke - but he has an awareness of the very mechanics his game is built upon. And not only is he aware of them, he has the ability to ''override'' most of them, something no other character in the game is shown to be able to do except [[EldritchAbomination Photoshop Flowey]] who has ''six human souls'' to his name.]] During the battle, he tells you [[spoiler:"look. i gave up trying to go back a long time ago. and getting to the surface doesn't really appeal anymore, either."]], suggesting he's somehow either in the wrong place, [[FishOutOfTemporalWater in the wrong time]], or both. And even though there's some dispute among fans that it might be ketchup, [[spoiler:something that definitely ''looks'' like blood spills out of him after he's cut open, despite the fact that monsters are MadeOfMagic and never shed blood]]. On top of all this, he's the only character in the game who we [[spoiler:[[SoundOnlyDeath never actually see turn to dust on-screen]]]], which some have taken as a suspiciously specific detail to include.
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* InexplicablyAwesome: Despite the fact that he's never trained a day in his life and has (presumably) been around for a tiny fraction of monster history, [[spoiler:he is far and away the single most powerful creature in the underground, and almost undoubtedly the among the smartest]]. This, combined with his awareness of [[spoiler:the game's mechanics and constantly-manipulated timeline]] almost make him feel like he's on another level compared to his peers, so much so that it's not unusual to find fans who are skeptical [[AmbiguouslyHuman if he's even a monster at all]]. Incomplete fragments of his backstory can be found scattered around the game, but we're clearly not getting anything definite anytime soon.
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* InexplicablyAwesome: Despite the fact that he's never trained a day in his life and has (presumably) been around for a tiny fraction of monster history, [[spoiler:he is far and away the single most powerful creature in the underground, and almost undoubtedly the easily among the smartest]]. This, combined with his awareness of [[spoiler:the game's mechanics and constantly-manipulated timeline]] almost make him feel like he's on another level compared to his peers, so much so that it's not unusual to find fans who are skeptical [[AmbiguouslyHuman if he's even a monster at all]]. Incomplete fragments of his backstory can be found scattered around the game, but we're clearly not getting anything definite anytime soon.
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[[caption-width-right:150:[[PungeonMaster i got a ton of work done today. a skele-ton.]]]]
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[[caption-width-right:150:[[PungeonMaster i got i've gotten a ton of work done today. a skele-ton.]]]]
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* InexplicablyAwesome: Despite the fact that he's never trained a day in his life and has (presumably) been around for a tiny fraction of monster history, [[spoiler:he is far and away the single most powerful creature in the underground, and almost undoubtedly the among the smartest]]. This, combined with his awareness of [[spoiler:the game's mechanics and constantly-manipulated timeline]] almost make him feel like he's on another level compared to his peers, so much so that it's not unusual to find fans who are skeptical [[AmbiguouslyHuman if he's even a monster at all]]. Incomplete fragments of his backstory can be found scattered around the game, but we're clearly not getting anything definite anytime soon.
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%%* PintsizedPowerhouse
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* YouCannotGraspTheTrueForm: He has the ability to [[spoiler:attack you ''in between turns'' by hitting your menu cursor.]] One can only imagine what an attack like that would translate to in-universe...
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* WideEyesAndShrunkenIrises: [[spoiler:The lights in his eyes become very small pinpricks of white after you mortally wound him.]]
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* WideEyesAndShrunkenIrises: [[spoiler:The lights in his eyes become very small pinpricks of white after you mortally wound him.]]
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* PintsizedPowerhouse: would fit as a trope image just fine.
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That's One Hit Point Wonder
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* GlassCannon: [[spoiler: Sans when serious is raw annihilation incarnate, and perhaps even more dangerous than [[TrueFinalBoss Asriel]] himself. ...He is ''also'' more fragile than ''Whimsun''. Seriously, he has '''''1 HP'''''. A ''stiff breeze'' could knock him over. Thankfully for Sans he is plenty aware of this, and is an absolute master of the art of dodging.]]
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* BlatantLies: [[spoiler:His combat description when you CHECK him says that he's the "easiest enemy in the game." This is... not quite accurate, to put it mildly, and since he leads with his strongest attack the moment the fight begins, the player will know it's a lie by the time they can read it.]]
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* BlatantLies: [[spoiler:His combat description when you CHECK him says that he's the "easiest enemy in the game." This is... not quite accurate, to put it mildly, is completely untrue, and since he leads with his strongest attack the moment the fight begins, the player will know it's a lie by the time they can read it.]]
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** [[spoiler:If you CHECK him in battle, he is described as "The easiest enemy. Can only deal 1 damage." This is ''technically'' true in that he has the worst stats in the game (only one ATK, DEF and [[OneHitPointWonder HP]]). But he dodges all your attacks, and his rapid-fire attacks override MercyInvincibility and leave behind residual damage, meaning every frame that heart touches his bone attacks will drop your HP rapidly, one by one.]]
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** [[spoiler:If you CHECK him in battle, he is described as "The easiest enemy. Can "Can only deal 1 damage." This is ''technically'' true in that he has the worst stats in the game (only one ATK, DEF and [[OneHitPointWonder HP]]). But true, but he dodges all your attacks, and his rapid-fire attacks override MercyInvincibility and leave behind residual damage, meaning every frame that heart touches his bone attacks will drop your HP rapidly, one by one.]]
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Not really seeing how that's exact words. He's got a different reason for judging you. How does that involve playing with a word's literal meaning.
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** He also uses this when he judges you on a Neutral run where you [[spoiler: kill Papyrus.]] He's not judging you for your viewpoint that it isn't your responsibility to do the right thing when asked about any "special power" you may have. No, he's judging you becase you're a [[spoiler: DIRTY BROTHER KILLER]].
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Dangerously Genre Savvy is for villains. Can't really by the villain and the Big Good. Also, Genre Savvy is not "Character is smart". It involves the character being familiar with in-universe fiction enough to be able to reasonably predict things based on what happened in said fiction.
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* CombatPragmatist: Where to begin? When he gets off his lazy butt, he can be quite DangerouslyGenreSavvy. [[spoiler: When he opens up his fight with you, he begins with a dramatic monologue, then proceeds to abruptly take the first turn, instead of letting you have it. Not only that, he uses it to unload his most powerful attack. If you die, [[SNKBoss (and you will - lots)]] and come back, ready for this trick, he will ''interrupt his own monologue and launch the attack early.'' He makes up for his lack of HP/Def by simply dodging out of the way of incoming attacks (and his speech seems to imply anyone is capable of it, but no one had ever thought of doing anything except just standing there and taking your hits before now) and his attacks completely ignore your MercyInvincibility. Halfway through the battle [[ISurrenderSuckers he offers you a Mercy option]] and, if you take it, he hits you with an unavoidable OneHitKill attack. As the fight goes on, he pulls pretty much every dirty trick you can imagine, including cutting between multiple attacks, and attacking you while you're navigating the menu screen. Finally, when all else fails, he unleashes his special attack: nothing. As in, he literally stands there doing nothing, refusing to allow you to take your turn, figuring that sooner or later you'll get bored and quit.]] The whole thing is probably best summed up with this one-liner:
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* CombatPragmatist: Where to begin? When he gets off his lazy butt, he can be quite DangerouslyGenreSavvy.savvy. [[spoiler: When he opens up his fight with you, he begins with a dramatic monologue, then proceeds to abruptly take the first turn, instead of letting you have it. Not only that, he uses it to unload his most powerful attack. If you die, [[SNKBoss (and you will - lots)]] and come back, ready for this trick, he will ''interrupt his own monologue and launch the attack early.'' He makes up for his lack of HP/Def by simply dodging out of the way of incoming attacks (and his speech seems to imply anyone is capable of it, but no one had ever thought of doing anything except just standing there and taking your hits before now) and his attacks completely ignore your MercyInvincibility. Halfway through the battle [[ISurrenderSuckers he offers you a Mercy option]] and, if you take it, he hits you with an unavoidable OneHitKill attack. As the fight goes on, he pulls pretty much every dirty trick you can imagine, including cutting between multiple attacks, and attacking you while you're navigating the menu screen. Finally, when all else fails, he unleashes his special attack: nothing. As in, he literally stands there doing nothing, refusing to allow you to take your turn, figuring that sooner or later you'll get bored and quit.]] The whole thing is probably best summed up with this one-liner:
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* DangerouslyGenreSavvy:
** Very much so. Pray he never shows you how much he understands how things work.
** [[spoiler: During a No Mercy run, he reveals that he's fully aware of your ability to save and reload the game, and the fact that you're slaughtering everyone more or less for your own amusement. Thus, his goal is not to just simply kill you, since you'll just keep trying until you beat him, his goal is to make his fight so frustrating and unfair that you (the player, not your character) simply RageQuit.]]
** [[spoiler: His "special attack" involves him literally doing nothing. He'll even repeatedly teleport you to the center of the bullet box ''just in case'' there is any possible funny business you can pull to try and escape; you have to wait until he's fallen asleep first before attempting to drag yourself over to the fight button. Even managing to do that is not enough due to Sans waking up to dodge and taunt just before you could strike him. He only goes down because you take your turn twice, catching him off guard with your second attack.]]
** Very much so. Pray he never shows you how much he understands how things work.
** [[spoiler: During a No Mercy run, he reveals that he's fully aware of your ability to save and reload the game, and the fact that you're slaughtering everyone more or less for your own amusement. Thus, his goal is not to just simply kill you, since you'll just keep trying until you beat him, his goal is to make his fight so frustrating and unfair that you (the player, not your character) simply RageQuit.]]
** [[spoiler: His "special attack" involves him literally doing nothing. He'll even repeatedly teleport you to the center of the bullet box ''just in case'' there is any possible funny business you can pull to try and escape; you have to wait until he's fallen asleep first before attempting to drag yourself over to the fight button. Even managing to do that is not enough due to Sans waking up to dodge and taunt just before you could strike him. He only goes down because you take your turn twice, catching him off guard with your second attack.]]
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%%Feel free to expand upon this page. Just know that's rife with spoilers
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Fixing typos as well as adding details to the excerpt.
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* DissonantSerenity: No matter how people react around him, Sans has the same big grin on. [[spoiler:This is implied to be an act, since he keeps this up even when it's clear he's in anguish or furious. He even keeps calm and casually talks about getting some food once he's mortally wounded.]]
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* DissonantSerenity: No matter how people react around him, Sans has the same big grin on. [[spoiler:This is implied to be an act, since he keeps this up even when it's clear he's in anguish or furious. He The only time he's even close to frowning is when you finally lay a hit on him. But, he keeps calm and casually talks about getting some food once he's mortally wounded.]]
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* BewareTheNiceOnes: An extremely chill and amiable guy, Sans is liked by everyone who knows him (except [[TheSociopath Flowey]], obviously) and treats you like an old friend mere seconds after you meet him. It usually takes a ''lot'' of effort to get Sans legitimately angry with you, but if you do... at best, [[spoiler:[[WhatTheHellPlayer he'll make you feel like complete garbage]], and at worst, ''[[ThatOneBoss say your prayers and hope it's over quickly]]''.]]
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* CrouchingMoronHiddenBadass: While he's clearly intelligent, Sans is ''incredibly'' lazy and prone to making immature jokes. [[spoiler:Definitely not the character you'd look to for ThatOneBoss material.]]
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* RelativeButton: While he will rightfully reprimand you for any evil that you do, the only way to truly get on Sans' bad side is killing his brother Papyrus. And oh boy, is it a bad side to get on...
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** He also uses this when he judges you on a Neutral run where you [[spoiler: kill Papyrus.]] He's not judging you for your viewpoint that it isn't your responsibility to do the right thing when asked about any [[ResetButton "special power"]] you may have. No, he's judging you becase you're a [[spoiler: DIRTY BROTHER KILLER]].
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** He also uses this when he judges you on a Neutral run where you [[spoiler: kill Papyrus.]] He's not judging you for your viewpoint that it isn't your responsibility to do the right thing when asked about any [[ResetButton "special power"]] power" you may have. No, he's judging you becase you're a [[spoiler: DIRTY BROTHER KILLER]].
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** He also uses this when he judges you on a Neutral run where you [[spoiler: kill Papyrus.]] He's not judging you for your viewpoint that it isn't your responsibility to do the right thing when asked about any [[ResetButton "special power"]] you may have. No, he's judging you becase you're a [[spoiler: DIRTY BROTHER KILLER]].
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[[center: [- [[Characters/{{Undertale}} Top Index]] | [[Characters/UndertaleMainCharacters Major]] | [[Characters/UndertaleOtherCharacters Minor]] | [[Characters/UndertaleMonsterEncounters Monsters]] | [[Characters/UndertaleSpoilerCharacters Spoilers]] ]] -]
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[[quoteright:150:http://static.tvtropes.org/pmwiki/pub/images/image25.png]]
[[caption-width-right:150:[[PungeonMaster i got a ton of work done today. a skele-ton.]]]]
A lazy skeleton who hates work and loves puns. He pops up here and there, usually touting some sketchy money-making scheme.
----
* AllLowercaseLetters: sans almost always speaks entirely in lower case and in his handwriting (to the point that one can tell something is said in-character as him simply by the lack of capitalization). You can tell that he is being ''deadly'' serious about something whenever he stops doing it.
* AlmightyJanitor: He's the Snowdin Forest watchman who is perfectly fine with shirking his duties and moonlighting with several other money-making schemes. He has 1HP and his attacks can only do 1 damage. [[spoiler:He also has a ''working knowledge'' of quantum physics, has figured out the timeline is being manipulated ''without'' a RippleEffectProofMemory, and is effectively TheDragon to Asgore. Oh, and those stats? His attacks ignore MercyInvincibility and apply a DamageOverTime effect, and he can ''dodge'' incoming attacks. IN SLIPPERS.]]
* AlphaStrike: [[spoiler: When you fight him in No Mercy, he opens with his strongest attack right away; a combination of GravityScrew, SpikesOfDoom, and BeamSpam with WaveMotionGun. If you don't know it's coming, you're almost guaranteed to die a few times until you get the pattern right.]]
-->'''Sans:''' [[spoiler: Huh. Always wondered why people never use their strongest attack first.]]
* AntiNihilist: The most [[SlidingScaleOfIdealismVersusCynicism optimistic]] way to [[AlternateCharacterInterpretation interpret his character]]. [[spoiler:He's pretty much resigned to his life, or lack thereof, being a thing determined by someone else's whim. He is nonetheless very jovial and friendly to pretty much everyone but those that deserve otherwise, tries to enjoy life to the best of his ability, and even laments having to kill you if you drive him to it.]]
-->'''Sans''': [[spoiler:sounds strange, but before all this i was secretly hoping we could be friends.]]
* AsideGlance: During his EstablishingCharacterMoment, he made two bad skeleton puns, followed by this and the requisite RimShot. [[spoiler: Also foreshadows that he knows about the meta nature of the game.]]
* AttackDrone: [[spoiler:Uses giant, floating, demonic skulls called "Gaster Blasters". They also fire [[{{WaveMotionGun}} wave motion beams]].]]
* AwakeningTheSleepingGiant: Sans is very, very lazy and generally disinterested in involvement beyond bad puns. [[spoiler:This is largely because the screwy time manipulation that's come about in the Underground has caused him to abandon hope of getting to the surface -- but he's still watching how things are playing out. Press his buttons one time too many over the adventure, and he'll decide he "[[LetsGetDangerous can't afford not to care anymore]]".]]
* AwesomenessByAnalysis: [[spoiler:While his time manipulation isn't as strong as being able to save, he's ''very'' good at filling in the blanks based on how you act and react to the events around you.]]
* BadassBoast: [[spoiler:He's full of these when he gets serious, but one in particular stands out.]]
--> '''Sans''': [[spoiler:heh heh heh heh...all right. well, here's a better question. do you wanna have a bad time? 'cause if you take another step forward...you are REALLY not going to like what happens next. ]]
* BadassOnPaper: Inverted, [[spoiler: checking his stats says that he has the worst stats in the game. While this ''is'' technically true, he ignores MercyInvincibility, his attacks are quite large, and he dodges every single attack while fighting you.]]
* BallisticBone: [[spoiler:His main form of attack. They also inflict [[DamageOverTime Karmic Retribution]]]].
* BeleagueredBureaucrat: He's implied to become this in [[spoiler:the Neutral ending where Papyrus becomes king by process of elimination. For the most part, all that Papyrus seems to do is make everyone spaghetti and listen to their problems, but he remarks that Sans is actually ''working'' a lot on things he's not entirely clear on, and hard at that, and that life has generally improved in the Underground.]]
* BeneathTheMask: Overlapping with {{Sad Clown}}, it's no surprise that Sans has a lot going on under his smiling skull. Even though he comes off as someone who truly enjoys pranking and making [[PungeonMaster bad puns]], Sans doesn't always speak in the goofy Comic Sans font and [[spoiler:he hides the worst secrets of the game. His laziness can be attributed to his heavy depression due to {{Eternal Recurrence}} he is trapped in and the friends he lost long time ago. He no longer cares about the world and had grown huge apathy towards his environment with only exceptions being [[LivingEmotionalCrutch Papyrus]] and the promise he made to Toriel.]] He usually sneaks in his real thoughts as "jokes", sometimes even the player wouldn't notice the hidden implications.
* BewareTheSillyOnes: Inverted trope, as he is a non-villainous example. While Sans tells bad skeleton puns and is incredibly lazy, [[spoiler:he can provide quite the ass-kicking when someone sets him off.]]
* BigBrotherInstinct: While unstated in-game, Sans is canonically older than Papyrus, and he is extremely protective of him and his happiness.
* BigBrotherWorship: Little brother, in this case; Sans makes it clear on many occasions how cool he genuinely finds Papyrus, for all he messes with him.
* BigGood: [[spoiler:Apparently regarded as a threat by the game's main villain Flowey (hence why he avoids letting him know he even exists), having a working knowledge of how saving/determination works, as well as being implied to have a straightforward time machine. He is on good terms with many other characters and even promised Toriel to protect humans. He also knows the true nature of EXP and LOVE and even explains it to you should you be doing a Neutral or Pacifist run. He faces you head on as the toughest boss fight in the game if you were to be playing on the No Mercy route (which ends in dire consequences that could never be fully recovered from in-game except through messing with the save files). That said, just how "good" he truly is is questionable, since he does state he would have killed the protagonist on the spot if it weren't for his promise to Toriel.]]
* BigGuyLittleGuy: The worldly, wisecracking, all-lower-case little guy to Papyrus' innocent, boisterous, all-capitals big guy. Sans is ostensibly in charge, paying for their house and all, but Papyrus is the one who keeps him on the straight and narrow.
* BigStupidDoodooHead: One of his [[spoiler:{{Trust Password}}s is "I'm a stupid doodoo butt". [[{{Troll}} Naturally, he asks Frisk to say the password to him]].]]
* BlatantLies: [[spoiler:His combat description when you CHECK him says that he's the "easiest enemy in the game." This is... not quite accurate, to put it mildly, and since he leads with his strongest attack the moment the fight begins, the player will know it's a lie by the time they can read it.]]
* BloodlessCarnage: Subverted [[spoiler: when you mortally wound him; blood pours out from his torso and mouth, despite him being a [[DemBones skeleton.]] Or maybe it's ketchup?]]
* BootstrappedLeitmotif: While Sans does indeed have a proper battle theme, MEGALOVANIA, Toby Fox's signature song, is often attributed to Sans [[spoiler:due to it being used as his boss theme]].
* BossRemix: "Song That Might Play When You Fight Sans".[[spoiler:Subverted in that it doesn't play at in the game. Instead, "MEGALOVANIA" plays.]]
* BrilliantButLazy: Sans is definitely this. [[spoiler:Despite all his shirking off duties and constant disappearances, not only is he well-aware of alternate playthroughs that you have made by which he will judge you accordingly but, during a full No Mercy run, '''he is the most dangerous monster in the entire game.''']]
* CatchPhrase: On a No Mercy run, before fighting Papyrus he tells you that if you keep this up "you're gonna have a bad time". [[spoiler: The line is used in his fight by the battle text.]]
* CasualDangerDialog: He has a lot to say to you throughout the entirety of [[spoiler:his boss battle]], he does so almost entirely with the exact same laid-back attitude he always does.
* CelibateHero: Sans is too lazy for a relationship, going by WordOfGod.
* CheshireCatGrin: His infamous [[http://pixelartmaker.com/art/bde9b0c674e6f35.png empty-eyed expression]], which he only makes when he wants to be cryptic or he ''really'' wants you to take him seriously.
* CombatPragmatist: Where to begin? When he gets off his lazy butt, he can be quite DangerouslyGenreSavvy. [[spoiler: When he opens up his fight with you, he begins with a dramatic monologue, then proceeds to abruptly take the first turn, instead of letting you have it. Not only that, he uses it to unload his most powerful attack. If you die, [[SNKBoss (and you will - lots)]] and come back, ready for this trick, he will ''interrupt his own monologue and launch the attack early.'' He makes up for his lack of HP/Def by simply dodging out of the way of incoming attacks (and his speech seems to imply anyone is capable of it, but no one had ever thought of doing anything except just standing there and taking your hits before now) and his attacks completely ignore your MercyInvincibility. Halfway through the battle [[ISurrenderSuckers he offers you a Mercy option]] and, if you take it, he hits you with an unavoidable OneHitKill attack. As the fight goes on, he pulls pretty much every dirty trick you can imagine, including cutting between multiple attacks, and attacking you while you're navigating the menu screen. Finally, when all else fails, he unleashes his special attack: nothing. As in, he literally stands there doing nothing, refusing to allow you to take your turn, figuring that sooner or later you'll get bored and quit.]] The whole thing is probably best summed up with this one-liner:
-->'''Sans''': [[spoiler:huh. always wondered why people never use their strongest attack first.]]
* CoolBigBro: For as much he enjoys messing with him, Sans' relationship with Papyrus is remarkably strong. He's laid-back, quick with a joke, and appears to be very popular with the town residents, yet he still considers his dorky manchild of a little brother the coolest person he knows.
* DamageOverTime: [[spoiler:In addition to massive direct damage when you touch them, his attacks also leave a slow damage over time effect called Karmic Retribution. The more you get hit, the longer this effect lasts.]]
* DangerouslyGenreSavvy:
** Very much so. Pray he never shows you how much he understands how things work.
** [[spoiler: During a No Mercy run, he reveals that he's fully aware of your ability to save and reload the game, and the fact that you're slaughtering everyone more or less for your own amusement. Thus, his goal is not to just simply kill you, since you'll just keep trying until you beat him, his goal is to make his fight so frustrating and unfair that you (the player, not your character) simply RageQuit.]]
** [[spoiler: His "special attack" involves him literally doing nothing. He'll even repeatedly teleport you to the center of the bullet box ''just in case'' there is any possible funny business you can pull to try and escape; you have to wait until he's fallen asleep first before attempting to drag yourself over to the fight button. Even managing to do that is not enough due to Sans waking up to dodge and taunt just before you could strike him. He only goes down because you take your turn twice, catching him off guard with your second attack.]]
* DeadpanSnarker: When his humor isn't puns, pranks, or some combination of the two, it's this, and many of his lines are dripping with it. Especially in response to Papyrus.
--> '''Papyrus''': YOU'RE SO LAZY!! YOU WERE NAPPING ALL NIGHT!!\\
'''Sans''': i think that's called... sleeping.
* DeathByIrony: [[spoiler:Sans spends entire fight playing on your expectations and trying to catch you off guard. How do you defeat him? By catching ''him'' off guard with a surprise attack while he taunts you after pulling yet another NonchalantDodge.]]
** [[spoiler:He can also inflict this on you. Earlier, Papyrus spared you and offered a hug, only to be killed while his guard was down. Midway through the fight with Sans, he tries to spare you. If you accept his mercy, he also offers a hug, then kills you while you're off-guard.]]
* DeathOfAThousandCuts: [[spoiler:Basically his combat strategy. Individually, his attacks are the weakest in the game. But they also avoid triggering your MercyInvincibility, and he can attack ''a lot''.]]
* DemBones: He's a talking skeleton who loves to eat and sleep.
* DespairEventHorizon: He's goofy and a PungeonMaster, but underneath that big grin, Sans... Sans is not well. [[spoiler:Living with the knowledge that at any second your life can be irrevocably snatched away from you every minute of the day tends to do that to a guy.]]
* DeterminedDefeatist: When he decides to step in and take action [[spoiler: at the end of Genocide run, he’s pretty much resigned to [[HopelessBossFight his tragic fate]]. But knowing that you’re about to destroy the world...he just can’t afford to not care anymore. He gives the player one hell of a final fight with the hopes of anomaly (the player) to RageQuit but at the end of the day, you are too [[SaveScumming determined]] to give up and he knows it from beginning to end.]]
* DissonantSerenity: No matter how people react around him, Sans has the same big grin on. [[spoiler:This is implied to be an act, since he keeps this up even when it's clear he's in anguish or furious. He even keeps calm and casually talks about getting some food once he's mortally wounded.]]
* DoNotTauntCthulhu: [[spoiler: Alright Sans, pulling off a ISurrenderSuckers combined with ForgivenessRequiresDeath is legit. But did you really ''have'' to tell us to get dunked? Because that might have infuriated most to redouble their effort to take you down.]]
* TheDreaded: [[spoiler:Anybody who has caused enough destruction to invoke Sans' wrath learns to fear him. Flowey states in a post-Neutral conversation that Sans is the only thing that has kept him from reaching Asgore on his No Mercy runs, and he's had to reset multiple times to avoid him; the only time Flowey gets the better of him is in the True Pacifist run by catching him and everyone else off-guard. The Fallen Child, despite being an immoral, emotionless murderer, will [[OOCIsSeriousBusiness express concern]] only when they have to fight Sans.]]
* DrosteImage: He keeps a joke book in his and Papyrus' house which hides a Quantum Physics textbook, which hides another joke book, [[RunningGag which hides another Quantum Physics textbook.]] [[HiddenDepths Pretty good metaphor for Sans himself, actually.]]
* DumpStat: His [[spoiler: HP, Defense and Attack are all 1. He doesn't need the first two as he can dodge extremely well and would die anyway from a single hit by the No Mercy Run protagonist, and his attack of 1 still deals ScratchDamage... ''without triggering MercyInvincibility''.]]
* EstablishingCharacterMoment: Stalking the protagonist in the woods outside Snowdin, only to reveal himself with the line "don't you know how to greet a new pal?". His hand-whoopie cushion establishes him as a good-natured prankster and {{Troll}} who doesn't work hard at all.
* ExactWords:
** Seems to be fond of these, in keeping with his persona as a ruthless prankster: Sans never actually lies to you [[spoiler:during his boss battle]], even though the implication of his words and his actions don't line up. [[spoiler:When asking you to Spare him, he says it would "make his job a lot easier," which is technically true in that he proceeds to kill the player while they are off guard, and once you do Spare him, he responds that he "won't let this go to waste," which he also doesn't... it's just that what he isn't wasting is his chance to take you out cleanly.]]
** [[spoiler:If you CHECK him in battle, he is described as "The easiest enemy. Can only deal 1 damage." This is ''technically'' true in that he has the worst stats in the game (only one ATK, DEF and [[OneHitPointWonder HP]]). But he dodges all your attacks, and his rapid-fire attacks override MercyInvincibility and leave behind residual damage, meaning every frame that heart touches his bone attacks will drop your HP rapidly, one by one.]]
** Most infamously, [[spoiler: when he uses his 'special attack', he says 'here goes nothing.' What happens next is...[[ExactlyWhatItSaysOnTheTin literally nothing]]. As in Sans ''refuses'' to end his turn, since knowing that as long as you get a chance to make your next move, you will kill him. So he simply waits, hoping that you'll get so bored that you'll give up and quit. Sadly for Sans, [[InterfaceScrew you give him a taste of his own medicine...]]]]
** A lighter instance can be seen in a post-it note argument Papyrus has with him.
--->'''Papyrus:''' SANS! PLEASE PICK UP YOUR SOCK!\\
'''Sans:''' ok.\\
'''Papyrus:''' DON'T PUT IT BACK DOWN! MOVE IT!\\
'''Sans:''' ok.\\
'''Papyrus:''' YOU MOVED IT TWO INCHES! MOVE IT TO YOUR ROOM!\\
'''Sans:''' ok.\\
'''Papyrus:''' AND DON'T BRING IT BACK!\\
'''Sans:''' ok.\\
'''Papyrus:''' IT'S STILL HERE!\\
'''Sans:''' didn't you just say not to bring it back to my room?\\
'''Papyrus:''' FORGET IT!
** [[spoiler:"Song That Might Play When You Fight Sans" is a remix of "sans." The song that actually plays is "MEGALOVANIA". The former isn't even in the game files.]]
* ExposedToTheElements: Not nearly as much as his brother, but he's still wearing shorts and slippers ''in the snow''.
* FamousLastWords:
--> [[spoiler:"papyrus, do you want anything?"]]
* FatalFlaw: He is really, ''really'' lazy, even if the cause of that is up for debate. While it's played for laughs every time it comes up for the most part, [[spoiler:he winds up exhausted should the player make it all the way to the end of his final barrage in No Mercy. From there, he starts to doze off...]]
** When Sans unleashes his special attack, (which turns out to be prolonging his turn to get you to quit) the only way to beat him is to [[spoiler: drag the box you're in over to the 'FIGHT' option. The only hint you're given to do this? Any time you get too close to the lower left-hand corner, Sans' eye flashes blue, and you are thrown back to the center. His precaution is ultimately what causes his death.]]
* TheFatalist: His humorous facade hides a deep and bitter cynicism. He stopped caring a long time ago and prefers to observe, rather than act. [[spoiler:However, he eventually gets motivated to take a stand near the end of the No Mercy run, despite acknowledging that due to your ability to reset, it's impossible for him to really win. The most he can hope is to get you to RageQuit.]]
* FatAndSkinny: The fat to Papyrus' skinny. He's surprisingly stocky for a skeleton, considering he doesn't have any flesh to speak of. [[StealthPun Because he's not fat, he's big-boned.]]
* {{Foreshadowing}}: Despite Sans downplaying Papyrus's abilities, he's definitely no pushover. [[spoiler:Sans has pretty high standards when it comes to power.]]
** Happens even earlier on in an easily-missed moment. [[spoiler:When you first enter Snowdin, there's a large branch in the path that's "too heavy to move", implying that it's fairly large. Once Sans starts following you, if you backtrack a bit, you'll notice that the branch has been ''snapped in half''. Considering Sans and the Human Child are about the same size... WOW.]]
* FinalBoss: [[spoiler: Of the No Mercy route. After him, you move onto Asgore who's automatically one-shotted, so he's the last true boss you'll fight.]]
* FragileSpeedster: [[spoiler:Sans takes this trope to its absolute conclusion. He is a OneHitPointWonder, but good luck getting even one hit in.]]
* FullContactMagic: [[spoiler:In his boss fight, he slams your soul into the walls and ceiling of the action box with a wave of his hand.]]
* FunetikAksent: His "-ing" words usually end in an "-in'", he says "'em" instead of "them", and he occasionally strings words together like "forgeddaboudit" and "howzabout it". Since the game has no voice acting, fans typically interpret this as some variety of New York accent.
* ForgivenessRequiresDeath: If you accept his offer of friendship in No Mercy Run.
--> [[spoiler: If we're really friends.... you won't come back.]]
* GameFace: Sans is always grinning, constantly looking around to make aside glances while he talks, giving him a cheerful, animated feel. [[spoiler: When his eyes disappear and he just ''stares'' straight at you with empty, pitch-black eye sockets, you know things have just gotten real. And when his left eye starts [[GlowingEyesOfDoom glowing]]... start praying, for all the good it will do.]]
** On the flip side, [[spoiler:his eyelights also disappear at one point in a Pacifist run, when he tells you his secret secret codeword: "I'm the legendary fartmaster.", implying confiding such, to him, is SeriousBusiness.]]
* GlassCannon: [[spoiler: Sans when serious is raw annihilation incarnate, and perhaps even more dangerous than [[TrueFinalBoss Asriel]] himself. ...He is ''also'' more fragile than ''Whimsun''. Seriously, he has '''''1 HP'''''. A ''stiff breeze'' could knock him over. Thankfully for Sans he is plenty aware of this, and is an absolute master of the art of dodging.]]
* GlowingEyelightsOfUndeath: His general expressions have those. They actually help making him look friendly and approachable (probably because of the artstyle). [[spoiler:They will disappear when he wants to sound threatening]].
* GlowingEyesOfDoom: [[spoiler:One of Sans's eyes glows as he uses various abilities during his battle, like Asgore.]]
* GoddamnedBoss: InvokedTrope. [[spoiler:He knows that you can just use SaveScumming to keep trying until you take him down, so he deliberately makes his fight as frustrating as possible to make you RageQuit.]]
* GodzillaThreshold: In the No Mercy run, [[spoiler:that would be ''you'', and the reason that Sans decided to get off his ass and try to stop you with anything he could muster, before you poison every timeline in the game.]]
* GoOutWithASmile: In the Genocide run, [[spoiler:despite probably being in immense pain from being slashed across the torso, he still manages to keep smiling even as he dies.]]
* GroundhogDayLoop: [[spoiler:Sans compares you starting and restarting the timeline via saves as this in the Genocide path as you're fighting him. Part of his laziness is because he knows how futile everything would be if it all resets again.]]
** Implied that [[spoiler: he forced Flowey into this as well, as the latter remarks how much he hates Sans for the number of resets Sans caused him.]]
* HardWorkHardlyWorks: Papyrus constantly tries his best to join the Royal Guard while Sans just mostly slacks off. [[spoiler:Yet Sans is by far the strongest of the two brothers.]]
* HeavySleeper: Sans appears to be rather lazy and can be seen sleeping on his job once. [[spoiler:This proves to be his undoing on the No Mercy route.]]
* HeroAntagonist: In the Genocide run, [[spoiler:he's the last fight before Asgore and the only character besides Undyne to give you any trouble. The flavor text, music, and general atmosphere of the fight all emphasize how ''Sans'' is the last line of defense between you and destruction of his world, and how the player deserves everything that's being thrown at them.]]
* HeroicBSOD: If you kill Papyrus, regardless of how few others you kill, [[spoiler:Sans completely disappears from the game until his judgment. He cares a '''lot''' about his brother.]]
* HeroOfAnotherStory: [[spoiler: It plain as day once you've learned what he knows that before Frisk came around, Sans was the only one working behind the scenes trying to save the Underground. He's been keeping tabs on the activity of the timeline, has been working diligently on some kind of machine in the basement of his home, and he keeps tabs on virtually the entire Underground with a little help from his teleporting shortcuts. To top it off, when you face him in the Genocide battle, he can attack you at all times and avoid all attacks, almost as if ''he'' was the player character and ''you'' were the boss monster. If you complete a few neutral runs in a row, Flowey would tell you to steer clear of Sans, as he had barred Flowey's path multiple times before, and caused him to reset. [[OffscreenMomentOfAwesome Successfully.]]]]
* HiddenDepths: [[spoiler:Sans tends to [[AlmightyJanitor keep a low profile]], but displays awareness of his alternate selves, the multiple timelines and resets, praises you if you didn't die up to the restaurant scene, counts the number of times he kills you, possesses incredible time-space abilities similar to yours and owns items such as the group shot you get by clearing a Pacifist run and choosing not to stay with Toriel. Just what is his deal?]]
* HopelessBossFight: [[spoiler:The fight in the No Mercy run is this. Not for you, but for ''him''. While he can (and will) kill you very quickly and messily, he knows it won't do any good since you can just reload your save and try again, and it's only a matter of time before you finally defeat him. The best he can hope for is to try to get you to RageQuit from the difficulty.]]
* HorrifyingTheHorror: [[spoiler: Both [[BigBad Flowey]] and [[GreaterScopeVillain The Fallen Child]] dread the moment Sans gets serious.]]
-->'''Flowey:''' [[spoiler: Say, if I have ONE piece of advice for you... DON'T. Let (Sans). Find out ANYTHING about you. He'll... well... Let's just say. He's caused me more than my fair share of resets. Stay away from him.]]
-->[[spoiler: "You feel like you're going to have a bad time".]]
* HumansAreTheRealMonsters: Some dialogue with him implies a distrust of humanity that runs deep, in contrast with his brother, who would at least give a human caught wandering the Underworld a fighting chance. Sans reveals he's less lenient in that regard when he confides to the player late in a Pacifist run that [[spoiler:he would've killed you the moment he saw you if Toriel hadn't made him promise not to harm any humans he came across.]]
* HoistByHisOwnPetard: [[spoiler: After an entire fight of throwing InterfaceScrew after InterfaceScrew at you, you beat his 'special attack' - i.e. him refusing to make his next move so you can never take your turn - by breaking the interface yourself, allowing you to press the Attack button in spite of it not being your turn.]]
* HPToOne: [[spoiler:Karmic Retribution will never reduce your health to 0. Similarly, you can't be killed getting hit by the bones in the menu while you're taking your turn, and his penultimate attack when he's bashing you against the walls won't drop you below 1.]]
* TheHyena: His VoiceGrunting is a low-pitched chuckle. Hehehehehehe...
* HyperAwareness: Sans may be the 'laziest' monster you'll meet in the Underground, but he's highly attentive to detail, down to subtle facial expressions. He also makes it a point to know and speak to everyone, getting a reading on personalities. He knows [[spoiler: through a combination of science, guesswork, and observation that a time-space anomaly has been ongoing for some time]]. It's implied that he's a competent tracker, should he stay awake long enough to do his job as a sentry.
* IconicOutfit: His hoodie/sport shorts/slippers combo.
* IGaveMyWord: Sans hates making promises, but if you can get him to make one, you bet your life he'll keep it. Case in point: you can ruthlessly slaughter just about anybody you want in the underground, up to and including his own brother, and despite the pain it clearly causes him, [[spoiler:he ''still'' won't break the promise he made to Toriel to keep you safe. Only once you're at the end of a genocide route and he knows for sure that you're going to destroy ''[[OmnicidalManiac everybody]]'' [[OmnicidalManiac and]] ''[[OmnicidalManiac everything]]'' if he lets you live does he finally set this commitment aside to try and stop you, and even then, the last thing he does before attacking you is apologize to her for it.]] This decision is somewhat justified, however, since [[spoiler:he's aware of your ability to reset the game, so he knows that you're more than likely going to start over shortly after you finish and everything will be back to normal. It's only on a genocide route that everything gets destroyed ''permanently'', hence him breaking the promise.]]
* IKnowYoureInThereSomewhereFight: [[spoiler: Sans' comments at the midway point of his boss fight has him call out to "someone who wanted to do the right thing", followed by a plea for them to let it end and reset. It's not made clear if he can remember a previous Pacifist run, can sense Frisk's kind heart beneath the OmnicidalManiac the Fallen is, or if he's simply bluffing, but it's clear he knows this ''isn't'' how it's suppose to be, and he's trying to get Frisk to realize that too. Unfortunately, Frisk is either [[LossOfIdentity completely gone]] or [[AndIMustScream still can't break free of your control]], so the effectiveness of this plea comes down to it reaching the player, not Frisk.]]
* InterfaceScrew: [[spoiler:Many of Sans' attacks abruptly change from one to the next, and during your turns he'll send bones through the menu to hit your SOUL cursor. He's able to change the direction of gravity during the Blue Heart phases as well]].
* IntergenerationalFriendship: With Toriel, as both of them really enjoy bad jokes. [[spoiler: Thanks to that, Sans didn't kill off Frisk the first time they met.]]
* IronicEcho: [[spoiler:Papyrus insists, in a Genocide playthrough, that anyone can be a good person if they try. Before fighting Sans, he asks you if you think "anyone can be a good person if they just try" before asking if you wanna have a bad time.]]
* ISurrenderSuckers: [[spoiler:Do you enjoy sparing people only to kill them when their guard is down? Well, if you think Sans is being sincere when he offers a truce to a mass murderer like you... [[KarmicDeath prepare to get dunked on.]] Besides just slashing him again, there's something that first-timers can look out for to realize he's faking. Remember how when enemies are in the sparing range, their names turn yellow? Sans' name does... but the "spare" option, which normally does as well, does not.]]
* IWarnedYou: [[spoiler: After you cut him down, before he stumbles offscreen and dies, he gives a defeated "welp, i warned you." He's very aware what's about to happen if you continue through the next two rooms and finish the playthrough, but it's no longer in his hands.]]
* IWillFightNoMoreForever: [[spoiler: With the little info on his backstory, the only clear part is that Sans wasn't always a "lazybones". For a long time he did his best to "fix" the broken machine in his basement; possibly to bring back people he lost and by extension, to get to the surface. Unfortunately the machine can not be fixed according to WordOfGod and Sans has no power to stop the resets. By the time you meet him, he's already resigned to [[EternalRecurrance his fate]] and doesn't care about going to surface or seeing his lost loved ones anymore.]]
* LaserGuidedKarma: [[spoiler:While fighting him, your life bar is under a "KR" effect that slowly decreases your HP like poison every time Sans hits you. Given cut battle narration lines in the script stating you're doomed by KARMA, it's safe to assume KR stands for Karmic Retribution. He also attempts to kill you by feigning a truce, much like you easily could have done for Toriel and many ordinary monsters at this point.]]
-->[[spoiler:''"You feel your sins crawling on your back."'']]
* LastStand: [[spoiler: His boss fight. Sans knows that your power to reset means that he can't beat you. But after seeing all the death left in your wake, knowing that you'll go on to destroy other timelines, and that there's no one else who can fight you, he decides he can't afford to not care anymore. Sadly, despite his best efforts to get you to give up, his laziness ends up costs him his life.]]
* LeaningOnTheFourthWall: More than a bit MediumAware. [[spoiler:He uses this to full effect when denying you your turn in the battle against him, thus denying you the ability to actually progress through the game. Also extended to how he treats your reloads, which he seems to observe from an in-universe perspective. While Flowey is actively aware of how you handle the timeline and abuses savestates to skip around, Sans seems to treat your different loads as alternate timelines and simply skips forwards in battle without any visible justification. The main method of figuring out you've reloaded? Not through hard evidence, but simply recognizing how you react to different things. "That look on your face...it means something."]]
* {{Leitmotif}}: The appropriately titled "sans." is a laid-back, quirky theme that suits him well. The song that plays when you have dinner with him is a remix of this song
* LethalJokeCharacter: [[spoiler:Sans is described as the easiest enemy who can do only a single point of damage per hit. As it turns out, what this really means is 1 ATK ''per frame''. And boy, does he take advantage of this to the extreme. Not only does he attack at ridiculous rates and in ridiculous amounts, but also, the 1 ATK means his attacks pierce MercyInvincibility to deal constant damage and leaving a poison effect. And they're some of the most ''intense'' in the entire game, because of the speed and range of his attacks (in some cases, there's literally just one tiny spot in the box where you can hide). He leaves the 1 defense point moot by constantly dodging your one hit kill swings.]]
* LetsGetDangerous: [[spoiler:In the No Mercy run, he comes to realize he can't stand by anymore, and resolves to finally do his job.]]
--> [[spoiler:all i know is...seeing what comes next...i can't afford not to care anymore.]]
* LosingHorns: When the Annoying Dog eats Papyrus' stash of bones and gets away, Sans peeks out of his room and plays a few mocking notes on a trombone.
* MagicFromTechnology: While he does have powers similar to Papyrus, Sans doesn't have [[spoiler:the power to SAVE or RippleEffectProofMemory]]. He shows that he can make up for it with a scientific background and, [[GuideDangIt if you can figure out how to access it]], [[spoiler:what is heavily implied to be a broken time machine in the locked room behind his house]].
* ManOfAThousandVoices. InUniverse example. He does a pretty good Toriel impression, insofar as you can tell from the sound of text scrolling.
* MarathonBoss: [[spoiler:Yes, he only has 1 HP. But you're faced to waste 22 turns just to try and get a chance to hit him, not including turns to stop to heal.]]
* MeaningfulName:
** He has a very comical personality, and [[PaintingTheMedium His speech is written]] in Comic Sans. He's also very lazy, and Comic Sans is often seen as a lazy choice. [[spoiler:Except when he's being serious, where it changes to a more conventional, "serious" sans-serif font (8bitoperator).]]
** "Sans" on its own means "without" or "lacking". [[spoiler:Which fits his hopeless view on the world, poor Sans is lacking in a lot of things.]]
** [[spoiler: Fans have taken this to mean all sorts of things. Sans, of course, is obviously a negation, but 'Serif' sounds like 'seraph', the angelic host, and something which a prophecy in the game predicted would appear -- an angel from the surface, guaranteed to remove everyone from the Underground.]]
** Averted for his battle theme, "Song That Might Play When You Fight Sans". [[spoiler: It doesn't play. "MEGALOVANIA" is his battle theme, but Sans isn't a megalomaniac. By that point, the psychotic power-hungry maniac is YOU.]]
* MediumAwareness: Sometimes displays this as part of a gag. [[spoiler: He knows MUCH more than he lets on, for instance, he's aware that the player can save and reset events at will. He's also aware of how battle structure works and tries defeating you by prolonging his turn, denying you your turn.]]
* MetaphoricallyTrue: [[spoiler:His stat readout lists him at 1 attack and 1 HP. And while that is technically true, he not only ''refuses'' to let your attacks land, but his attacks continually deal 1 HP for every instant their hitboxes make contact with you ''and'' apply a poison effect that ticks down at - you guessed it - 1 damage a second.]]
* MindOverMatter: [[spoiler:His ability to slam the your character's SOUL against the inside of the battle box via hand motions seems to suggest he can do this.]]
* MouthFlaps: Averted. Sans noticeably never seems to opens his mouth to talk.
* MysteriousPast: Oh, absolutely. The game has deliberately-placed hints about his prior life littered throughout it, all of them vague but heavy in their implication. There's a reason he and [[spoiler:his relative/friend/co-worker/''something'' W.D Gaster]] have spawned more speculative fan material than any other characters.
* MundaneUtility: [[spoiler:Uses both his time manipulation and his incredible guesswork to set up a prank that transcends time. And according to Papyrus, he does things like this frequently.]] He also teleports himself and friends anywhere and everywhere for any reason, the most common reason being "a cheap joke".
* MyFriendsAndZoidberg: [[spoiler:A schedule of events can be found at the MTT Resort advertising "performers, comedians, and Sans."]]
* NiceGuy: [[SurpriseCreepy Occasional creepy moments aside]], he's very friendly and always treats the player like an old buddy, even after they just met. [[spoiler:Makes sense after all, he's well aware that this most likely is not the first time he's met the player; him befriending them is his way to make a potentially genocidal player think twice about going through with it. He has his limits, however: kill his brother and he'll want nothing to do with the player, only appearing again to tell them off at the end of the game. Probably the only reason why he doesn't make them [[SNKBoss have a bad time]] then and there after killing Papyrus out of rage is because the player can still reset the timeline, thus undoing his battle/murder.]]
* NonchalantDodge: [[spoiler:Sans can sidestep your attacks. [[LampshadeHanging Well, why doesn't anyone else?]] ...But then it's subverted to disturbing effect when the player character spams the attack button [[DiagonalCut and slices him in two.]]]]
* NoNonsenseNemesis: [[spoiler: Granted, it takes ''a lot'' to push Sans into dropping the nonsense and becoming your nemesis, and even that is ''only'' because he made a promise to Toriel, but once you've crossed the final line of no return and there are no other options left, he'll cut out the puns and... well, the CombatPragmatist section up there can tell you all about it... "You feel like you're going to have a bad time" ''indeed''.]]
* OffscreenTeleportation: Sans can warp around when out of sight and often shows up way ahead of you through the areas [[TookAShortcut for no explained reason.]] [[spoiler:The abilities he displays during his battle suggest he has some control over time and space like you and Flowey do.]]
** Subverted for once in Genocide Route. [[spoiler: He tells you that you will have a bad time if you continue, then the screen blinks, and he's gone.]] It makes for a very creepy moment.
* OhCrap: His expression just before [[spoiler:he is sliced in half.]]
* OlderThanTheyLook: His age is extremely vague, but he's clearly an adult. Despite this, his overworld sprite is almost eye-to-eye with the player character's, and his presumably more-proportionate battle sprite is still squat enough to give the impression that he's a child.
* OneHitKO: [[spoiler:Partway through the fight, Sans will offer to spare you. This is a trap; if you accept this offer, Sans will fill up the combat box with bones arranged in a jail-cell pattern that ''can't be dodged'', taking off all your health and resulting in a game over.]]
* OneHitpointWonder: [[spoiler: Sans has one HP, but he is still the hardest boss in the game.[[note]]In practice, he has 22 HP, because his script only advances when you attack him. I.E. to get to his "special attack" (whereupon you can end the battle) you need to attack him 22 times.[[/note]]]]
* OOCIsSeriousBusiness: Sans is almost always cracking wise or lazing about, seemingly without a care in the world. Yet he has his moments of gravity, and when it comes time to deliver them, [[GameFace his pupils fade into darkness]], his VoiceGrunting disappears (often taking the background music with it), and he loses his AllLowercaseLetters speaking style. He even changes fonts (he usually speaks in Comic Sans, but switches to the sans-serif 8bitoperator for his serious lines). Also, if it's your fault that Sans finally decides to [[LetsGetDangerous stop being lazy]], well... [[ThisIsGonnaSuck you're gonna have a bad time.]]
* PaintingTheMedium: To start, Sans speaks in comic sans. Secondly, he spends most of the game talking in AllLowercaseLetters... but at random he'll leave his I's capitalized, and he will sometimes use apostrophes correctly but sometimes won't. Yes, Sans is so lazy he can't even use AllLowercaseLetters consistently. Or to put it another way, Sans speaks like he's ''typing'' but is too lazy to type properly; now remember that Toby Fox had to type all of Sans' dialogue.
* PerpetualSmiler: Sans always has a mysterious smug, sneaky air about him, at least [[spoiler:when he's not exuding a TranquilFury attitude]] instead. Even when his eyes are giving away a different emotion, his giant grin never moves, most likely because he's a [[DemBones skeleton.]] The closest his grin ever changes is [[spoiler: when your blow finally connects,]] and even then it's just barely.
* PintsizedPowerhouse: would fit as a trope image just fine.
* PlatformHell: [[spoiler: Most of his attacks are done while your heart is Blue; they're fast, tricky to dodge, and deal a crapload of damage.]]
* ThePrankster: Not only does Sans love bad jokes and puns, he also likes to pull harmless pranks on the protagonist. Whoopie cushions in the hand and on the chair, loosening the cap on a ketchup bottle and having paint in a telescope's eyepiece stand out.
* PreAssKickingOneliner: [[spoiler:"it's a beautiful day outside. birds are singing, flowers are blooming... on days like these, kids like you... '''Should be burning in hell.'''" This is even played with to mess with you even further - he'll cut the speech off mid-sentence and immediately jump into his opening routine entirely at random.]]
* PungeonMaster: Sans enjoys harassing Papyrus with bad skeleton-related puns.
* RealityWarper: Very much so. If you also survive his penultimate attack, ''he flips out'', and starts throwing you around everywhere, in what truly is the only unavoidable attack in the entire bullet-hell game.
* TheReasonYouSuckSpeech: [[spoiler:Delivers one to the player in the second stage of his battle, questioning why they want to destroy his world so badly. Given that this happens after his attempts to stop the player through trickery and just plain making the battle difficult have failed, doubles as an attempt to BreakThemByTalking.]]
--> [[spoiler:i always thought the anomaly was doing this cause they were unhappy. and when they got what they wanted, they would stop all this... but that's ridiculous, right? yeah, you're the type of person who won't EVER be happy.]]
* RedOniBlueOni: The blue to Papyrus' red (blue clothing, calm personality...).
* RhetoricalQuestionBlunder: Meta-wise. Do you feel bad for killing Papyrus? Invoke WellIntentionedExtremist, and you can do just that without feeling awful.
-->'''Sans:''' Then why did you kill my brother?\\
[[spoiler: '''You:''' This is for the best.]]\\
'''Sans, later on:''' [[spoiler: This is the best life. Thanks.]]
* RoaringRampageOfRevenge: [[spoiler: He ''unleashes hell on you'' for all the innocent lives you've taken, and if you went and killed Papyrus as well, he's already let you know before this that you've well and broken his last straw.]]
* SadClown:
** [[spoiler:Alluded to when facing him as a Lost Soul, and explicitly stated when fighting him on a No Mercy run. His knowledge of the player's and Flowey's interference with the timeline (through saving and resetting), and the belief that things will inevitably be reset again in the future, has left him exhausted and existentially depressed. It's implied that this also has something to do with W.D. Gaster and the strange machine Sans is working on...]]
** Sans also displays a degree of self-loathing, most notably in the ending where [[spoiler: you kill all of the important characters, leaving the Underground utterly bereft of leaders. Sans talks about why he didn't take up the throne and explains that it isn't his style, and that he prefers to take things easy... before explaining that that was a joke and the whole mess they're stuck in is exactly what happens when "people like [him]" take it easy.]]
* SealedEvilInADuel: [[spoiler: Attempted. His 'Special Attack' is simply to start his turn... and never end it. He outright says that he intends to just sit there until you get bored and turn off the game. Unfortunately, he falls asleep after a while, allowing you to kill him anyways.]]
* SeriesMascot: While Flowey has been pushed to being one, Sans has a lot of icon power on the internet to the point where people who have only glanced at Undertale but never played it can probably recognize what game he's from when they see him elsewhere. Tends to happen when you're one of the most liked characters [[spoiler: and a freakishly difficult and memorable BonusBoss, which is verging on ItWasHisSled in most circles.]]
* SetRightWhatOnceWentWrong: [[spoiler:A photograph in Sans' room reveals that there was once a timeline where Sans was surrounded by friends "you don't recognize". Between his comments that he, "gave up trying to go back a long time ago" and Flowey talking about how many resets Sans has cost him, it's fair to assume Sans spent a ''lot'' of time trying to undo a particularly heartless edit to the timeline]].
* ScrewTheRulesImDoingWhatsRight: [[spoiler: When facing him at the end of a No Mercy Run, he disregards many of the established mechanics in the game and fights dirty - interrupting his dialog to open with a brutal first strike, ignoring MercyInvincibility with his attacks, dodging your swings, feigning surrender, attacking while you're in the menu, and using his last turn to bore you into submission. All as a last ditch effort to stop you from killing everyone.]]
* SheatheYourSword: [[spoiler:What his special attack turns out to be -- he just never ends his turn, meaning ''you'' never get ''yours'', unless you find a way to cheat the system.]]
* TheSlacker: Sans takes laziness to an art form. At one point he converts a guard booth into a makeshift shop to hawk food to passersby. As an impressed Papyrus notes, he's not doing his job by ''doing another job.''
* SmugSuper: Sans definitely doesn't understate his own power when pushed far enough to use it. [[spoiler: In the No Mercy run, if the player loses to him (and they will - a LOT), he'll keep rubbing it in their face the first twelve times after reloading a save. Afterwards, he'll ditch the showing-off, and go straight into obliteration mode.]]
-->'''Sans:''' [[spoiler: do you wanna have a bad time? 'cause if you take another step forward...you are REALLY not going to like what happens next.]]
-->'''Sans [[spoiler: (After losing against him for the first time):]]''' [[spoiler: you look frustrated about something. guess i'm pretty good at my job, huh?]]
* SNKBoss: [[spoiler: A non-fighting game example. He breaks damn near every rule of the game (and of turn-based [=RPGs=] in general) when fighting you and is far and away the hardest fight in the game to boot.]]
* SoundOnlyDeath: Sans is the only [[spoiler:character you can kill that you don't get to see die onscreen. After you deliver the final blow, he resigns to his fate, then shuffles offscreen. Seconds later, you hear the "monster turns to dust" sound.]]
* TheSouthpaw: Close observation suggests that Sans is a lefty: he offers his left hand to shake hands at the start of the game, and at Grillby's he uses his left hand when he chugs an entire bottle of ketchup. [[spoiler:He also uses his left hand to smear you across the walls, floor, and ceiling with the gravity power of the Blue SOUL attack if you face him on a No Mercy run.]]
* TheSpook: Apparently he and his brother just sort of showed up in Snowdin one day. With Papyrus, it's less apparent, since he wears his heart on his shoulder, but Sans keeps most people at an arm's length, and it's never made explicitly clear just how much he knows about (or is involved in) any given plot point, though it's at least a fair bet to say "significantly."
* StandardStatusEffects: [[spoiler:Karmic Retribution has a damage-over-time effect, similar to a poison/bleeding effect. The more you've been hit, the more damage you take from it.]]
* StepfordSmiler: To varying degrees, depending on how the player affects the world and how hopeful things seem. [[spoiler:Even on the best possible path, he has enough awareness of just how easily things can be turned back that it's very likely a contributor to his lazy demeanor.]]
* StoppedCaring: He doesn't seem to care about anything aside from bad jokes and his brother. [[spoiler:He's figured out that someone or something has been resetting and manipulating the timeline, and has given up trying to stop them... aside from befriending everyone he meets in the hope that one of them is the source, and he can finally make them happy]].
* StrongerSibling: [[spoiler:His brother Papyrus is a BadAss of his own right... But Sans is far, far more powerful than him. One shudders to think what would happen if he actually trained.]]
* TacticalSuicideBoss: [[spoiler: There's always a way to dodge his attacks, allowing you to weather his barrages and exhaust him. But he's shown capable to perform inescapable attacks too, so there's really no reason why he'd provide platforms for you to survive his attacks other than [[{{Unwinnable}} a purely gameplay perspective.]]]]
* TalkToTheFist: [[spoiler: He's the only enemy in the game who gets the first turn in combat, very likely catching you off-guard. And if you think you can try skipping his intro speech, [[BeCarefulWhatYouWishFor he'll gladly oblige]] and cut off his speech abruptly straight into his opening barrage.]]
* TeleportSpam: [[spoiler: Sans can bend time and space to a degree, and he abuses this ''liberally''. The entire game he teleports his sentry station from Snowdin around as a hot dog stand (you can even see the snow still on the roof, and a monster comments on that) and he repeatedly takes "shortcuts" by walking in the ''complete opposite direction'' of his destination and [[OffscreenTeleportation arriving there in-between screen transitions]], anyways.]]
* ThisIsGonnaSuck: [[spoiler:If you survive his opening barrage in the boss fight, he immediately opens his eyelights again and says "here we go"]].
--> [[spoiler:''"You feel like you're going to have a bad time."'']]
* TooDumbToLive: [[spoiler:When fighting him on the Genocide Route, he knows full well that you're a time-warping unkillable demigod, and his strategy is not to kill you, since he knows that's impossible, but rather to annoy the shit out of you until you RageQuit, thereby saving the world from you. Sound enough strategy. But the problem is that if you defeat him and then spare him... he'll stab you in the back and kill you despite the possibility that your mercy was genuine, thereby guaranteeing that you will try to kill him next time you fight, a fight you just established you're capable of winning.]] To be fair, [[spoiler:he does tell you what to do on the game over screen if your mercy was indeed genuine; quit the game and reset.]]
* TrademarkFavoriteFood: He seems to like to drink condiments like ketchup like a beverage.
* TranquilFury: Sans, of course, is a very chill skeleton...[[spoiler:and the most chilling thing about him is his no-nonsense font and lightless sockets if you manage to piss him off.]] Taken UpToEleven during [[spoiler:the final battle with him, where he's ''still'' grinning with one hand in his pocket as he ''pulverizes'' you with the other one, one of his eyes literally flashing with rage.]]
* TrashOfTheTitans: [[spoiler:His room turns out to have a literal trash storm in it]].
* {{Troll}}: It's pretty much his M.O. One of the best (and arguably most hilarious) instances of this is during [[spoiler: his boss fight, should you accept his offer of mercy (and get hit with the subsequent - and completely unavoidable - OneHitKill attack).]] The "Game Over" music will be replaced with a sped-up version of the goofy "Dog Song" track as Sans mocks you. Reload the game and talk to him again and he'll mention how incredibly pissed off you look.
-->'''Sans:''' geeettttttt dunked on!!
* TrustPassword: [[spoiler:If you reload a save after listening to his Judgment during a Pacifist run, he will give you one of these that, if you reset and talk to him again, will utterly fail to convince him that you're a time traveller. He will, however, give you a ''second'' password that, when reset and told to him again, causes him to give you a key to his room. The passwords are, respectively, [[{{Troll}} "I'm a stupid doodoo butt" and "I'm the legendary fartmaster."]]]]
* TurnsRed: [[spoiler:While other bosses get gradually more difficult, Sans does his difficulty spike all at once. Once you reject his offer of mercy, he'll step up his game. This is the part where he outright starts cheating, unleashing combos that require you to do different things and attacking you while it's your turn.]]'
* UnexplainedAccent: As mentioned above, he seems to have some variety of New Yorkian accent. Pretty weird coming from a guy who's spent his entire life underground among monsters who mostly lack readable accents, especially since his own ''brother'' doesn't even have one.
* VideoGameCrueltyPunishment: He will judge you near the end of your journey, and he has some [[PlayerPunch choice words]] should you engage in VideoGameCrueltyPotential. [[spoiler: And if you've been going for the KillEmAll route, he bars your path as ''the'' single toughest boss in the game.]]
* VitriolicBestBuds: He deliberately annoys his brother Papyrus almost every second they're on screen together, who constantly nags and complains about him back, but it's always in good nature and they're nothing if not completely dedicated to each other. Sans even mentions in an optional piece of dialogue that he appreciates Papyrus' nagging, since it's the only thing that [[TheSlacker actually motivates him to do anything productive]].
* WalkingSpoiler: There's quite a bit more to Sans than just the joke-loving skeleton you meet early on. Those avoiding spoilers take heed: even glancing at fanart of Sans gives away a lot about his character.
* WaveMotionGun: [[spoiler: His "Gaster Blasters", which are skull-like cannons that fire off massive beams in a straight line with little to no time spent to let you get a sense for their angle. Sans is capable of summoning multiples at once at varying sizes and patterns to catch you out, they're easily one of his hardest to dodge attacks, and given the entire fight is ridiculously hard, that says something.]]
* WeakButSkilled: [[spoiler:Technically speaking, he really is the weakest enemy in the game, having only 1 HP and only capable of doing 1 damage. He makes up for it through clever abuse of game mechanics. He only has 1 HP, but he dodges all of your attacks instead of just taking them like every other monster in the game. He knows 1-damage attacks don't trigger the invincibility period, so he does 1 damage ''per frame''. That's not even getting into his SPARE trick, or his "special attack". Indeed, the only reason you can even kill him is by breaking the game -- dragging your SOUL over to the ATTACK button ''during his turn.'']]
* WideEyesAndShrunkenIrises: [[spoiler:The lights in his eyes become very small pinpricks of white after you mortally wound him.]]
* WhamLine: Sans has several which are said WITHOUT his usual 'accent' of Comic Sans, such as...
--> [[spoiler:''"You'd be dead where you stand."'' - referencing that if Toriel hadn't asked him to leave you be, he would've instantly killed you the moment he saw you.]]
--> [[spoiler:''"LOVE, too, is an acronym."'' - Near the end, the not-so-goofy Sans reveals the true nature of your stats and judges your actions.]]
--> [[spoiler:''"You dirty brother killer."'' - Only said if you kill Papyrus but aren't on a No Mercy run.]]
--> [[spoiler:''"If you keep going the way you are now... you're gonna have a bad time."'' - Said on the No Mercy run, in place of what was previously innocuous advice about the upcoming boss battle. He teleports away immediately after, which is also the only time in the game you actually ''see'' him teleport, with a very creepy effect.]]
--> ''"What? You think I'm just gonna stand there and take it?"'' [[spoiler: Upon dodging the one-hit kill strike that felled so many bosses beforehand.]]
* WorldsBestWarrior: [[spoiler: There is not a soul in the Underground more deadly than the short, goofy pun-lover. Sure, he might be the physically weakest monster there, but he'll essentially break reality to take you down.]]
* WouldHurtAChild: Claims he would've killed you the moment he first saw you were it not for [[spoiler: his promise to Toriel]], and on a No Mercy/No Mercy run [[spoiler: he actually does it (or tries to, anyway.)]]
--> '''Sans:''' it's a beautiful day outside. birds are singing, flowers are blooming. on days like these, kids like you...[[spoiler: '''Should be burning in hell.''']]
* YankTheDogsChain: [[spoiler:If the player's earned the True Ending, in subsequent play-throughs he'll have a copy of the group photograph that you're given where you choose to not stay with Toriel. The fact that he has it means that he's at least aware of the True Ending where everyone gets to survive and reach the surface... and then seen all that undone.]]
* YouBastard: [[spoiler: If the player kills Papyrus on a Neutral run they will get called out by Sans as a "DIRTY BROTHER KILLER."]]
* YouCannotGraspTheTrueForm: He has the ability to [[spoiler:attack you ''in between turns'' by hitting your menu cursor.]] One can only imagine what an attack like that would translate to in-universe...
----
[[caption-width-right:150:[[PungeonMaster i got a ton of work done today. a skele-ton.]]]]
A lazy skeleton who hates work and loves puns. He pops up here and there, usually touting some sketchy money-making scheme.
----
* AllLowercaseLetters: sans almost always speaks entirely in lower case and in his handwriting (to the point that one can tell something is said in-character as him simply by the lack of capitalization). You can tell that he is being ''deadly'' serious about something whenever he stops doing it.
* AlmightyJanitor: He's the Snowdin Forest watchman who is perfectly fine with shirking his duties and moonlighting with several other money-making schemes. He has 1HP and his attacks can only do 1 damage. [[spoiler:He also has a ''working knowledge'' of quantum physics, has figured out the timeline is being manipulated ''without'' a RippleEffectProofMemory, and is effectively TheDragon to Asgore. Oh, and those stats? His attacks ignore MercyInvincibility and apply a DamageOverTime effect, and he can ''dodge'' incoming attacks. IN SLIPPERS.]]
* AlphaStrike: [[spoiler: When you fight him in No Mercy, he opens with his strongest attack right away; a combination of GravityScrew, SpikesOfDoom, and BeamSpam with WaveMotionGun. If you don't know it's coming, you're almost guaranteed to die a few times until you get the pattern right.]]
-->'''Sans:''' [[spoiler: Huh. Always wondered why people never use their strongest attack first.]]
* AntiNihilist: The most [[SlidingScaleOfIdealismVersusCynicism optimistic]] way to [[AlternateCharacterInterpretation interpret his character]]. [[spoiler:He's pretty much resigned to his life, or lack thereof, being a thing determined by someone else's whim. He is nonetheless very jovial and friendly to pretty much everyone but those that deserve otherwise, tries to enjoy life to the best of his ability, and even laments having to kill you if you drive him to it.]]
-->'''Sans''': [[spoiler:sounds strange, but before all this i was secretly hoping we could be friends.]]
* AsideGlance: During his EstablishingCharacterMoment, he made two bad skeleton puns, followed by this and the requisite RimShot. [[spoiler: Also foreshadows that he knows about the meta nature of the game.]]
* AttackDrone: [[spoiler:Uses giant, floating, demonic skulls called "Gaster Blasters". They also fire [[{{WaveMotionGun}} wave motion beams]].]]
* AwakeningTheSleepingGiant: Sans is very, very lazy and generally disinterested in involvement beyond bad puns. [[spoiler:This is largely because the screwy time manipulation that's come about in the Underground has caused him to abandon hope of getting to the surface -- but he's still watching how things are playing out. Press his buttons one time too many over the adventure, and he'll decide he "[[LetsGetDangerous can't afford not to care anymore]]".]]
* AwesomenessByAnalysis: [[spoiler:While his time manipulation isn't as strong as being able to save, he's ''very'' good at filling in the blanks based on how you act and react to the events around you.]]
* BadassBoast: [[spoiler:He's full of these when he gets serious, but one in particular stands out.]]
--> '''Sans''': [[spoiler:heh heh heh heh...all right. well, here's a better question. do you wanna have a bad time? 'cause if you take another step forward...you are REALLY not going to like what happens next. ]]
* BadassOnPaper: Inverted, [[spoiler: checking his stats says that he has the worst stats in the game. While this ''is'' technically true, he ignores MercyInvincibility, his attacks are quite large, and he dodges every single attack while fighting you.]]
* BallisticBone: [[spoiler:His main form of attack. They also inflict [[DamageOverTime Karmic Retribution]]]].
* BeleagueredBureaucrat: He's implied to become this in [[spoiler:the Neutral ending where Papyrus becomes king by process of elimination. For the most part, all that Papyrus seems to do is make everyone spaghetti and listen to their problems, but he remarks that Sans is actually ''working'' a lot on things he's not entirely clear on, and hard at that, and that life has generally improved in the Underground.]]
* BeneathTheMask: Overlapping with {{Sad Clown}}, it's no surprise that Sans has a lot going on under his smiling skull. Even though he comes off as someone who truly enjoys pranking and making [[PungeonMaster bad puns]], Sans doesn't always speak in the goofy Comic Sans font and [[spoiler:he hides the worst secrets of the game. His laziness can be attributed to his heavy depression due to {{Eternal Recurrence}} he is trapped in and the friends he lost long time ago. He no longer cares about the world and had grown huge apathy towards his environment with only exceptions being [[LivingEmotionalCrutch Papyrus]] and the promise he made to Toriel.]] He usually sneaks in his real thoughts as "jokes", sometimes even the player wouldn't notice the hidden implications.
* BewareTheSillyOnes: Inverted trope, as he is a non-villainous example. While Sans tells bad skeleton puns and is incredibly lazy, [[spoiler:he can provide quite the ass-kicking when someone sets him off.]]
* BigBrotherInstinct: While unstated in-game, Sans is canonically older than Papyrus, and he is extremely protective of him and his happiness.
* BigBrotherWorship: Little brother, in this case; Sans makes it clear on many occasions how cool he genuinely finds Papyrus, for all he messes with him.
* BigGood: [[spoiler:Apparently regarded as a threat by the game's main villain Flowey (hence why he avoids letting him know he even exists), having a working knowledge of how saving/determination works, as well as being implied to have a straightforward time machine. He is on good terms with many other characters and even promised Toriel to protect humans. He also knows the true nature of EXP and LOVE and even explains it to you should you be doing a Neutral or Pacifist run. He faces you head on as the toughest boss fight in the game if you were to be playing on the No Mercy route (which ends in dire consequences that could never be fully recovered from in-game except through messing with the save files). That said, just how "good" he truly is is questionable, since he does state he would have killed the protagonist on the spot if it weren't for his promise to Toriel.]]
* BigGuyLittleGuy: The worldly, wisecracking, all-lower-case little guy to Papyrus' innocent, boisterous, all-capitals big guy. Sans is ostensibly in charge, paying for their house and all, but Papyrus is the one who keeps him on the straight and narrow.
* BigStupidDoodooHead: One of his [[spoiler:{{Trust Password}}s is "I'm a stupid doodoo butt". [[{{Troll}} Naturally, he asks Frisk to say the password to him]].]]
* BlatantLies: [[spoiler:His combat description when you CHECK him says that he's the "easiest enemy in the game." This is... not quite accurate, to put it mildly, and since he leads with his strongest attack the moment the fight begins, the player will know it's a lie by the time they can read it.]]
* BloodlessCarnage: Subverted [[spoiler: when you mortally wound him; blood pours out from his torso and mouth, despite him being a [[DemBones skeleton.]] Or maybe it's ketchup?]]
* BootstrappedLeitmotif: While Sans does indeed have a proper battle theme, MEGALOVANIA, Toby Fox's signature song, is often attributed to Sans [[spoiler:due to it being used as his boss theme]].
* BossRemix: "Song That Might Play When You Fight Sans".[[spoiler:Subverted in that it doesn't play at in the game. Instead, "MEGALOVANIA" plays.]]
* BrilliantButLazy: Sans is definitely this. [[spoiler:Despite all his shirking off duties and constant disappearances, not only is he well-aware of alternate playthroughs that you have made by which he will judge you accordingly but, during a full No Mercy run, '''he is the most dangerous monster in the entire game.''']]
* CatchPhrase: On a No Mercy run, before fighting Papyrus he tells you that if you keep this up "you're gonna have a bad time". [[spoiler: The line is used in his fight by the battle text.]]
* CasualDangerDialog: He has a lot to say to you throughout the entirety of [[spoiler:his boss battle]], he does so almost entirely with the exact same laid-back attitude he always does.
* CelibateHero: Sans is too lazy for a relationship, going by WordOfGod.
* CheshireCatGrin: His infamous [[http://pixelartmaker.com/art/bde9b0c674e6f35.png empty-eyed expression]], which he only makes when he wants to be cryptic or he ''really'' wants you to take him seriously.
* CombatPragmatist: Where to begin? When he gets off his lazy butt, he can be quite DangerouslyGenreSavvy. [[spoiler: When he opens up his fight with you, he begins with a dramatic monologue, then proceeds to abruptly take the first turn, instead of letting you have it. Not only that, he uses it to unload his most powerful attack. If you die, [[SNKBoss (and you will - lots)]] and come back, ready for this trick, he will ''interrupt his own monologue and launch the attack early.'' He makes up for his lack of HP/Def by simply dodging out of the way of incoming attacks (and his speech seems to imply anyone is capable of it, but no one had ever thought of doing anything except just standing there and taking your hits before now) and his attacks completely ignore your MercyInvincibility. Halfway through the battle [[ISurrenderSuckers he offers you a Mercy option]] and, if you take it, he hits you with an unavoidable OneHitKill attack. As the fight goes on, he pulls pretty much every dirty trick you can imagine, including cutting between multiple attacks, and attacking you while you're navigating the menu screen. Finally, when all else fails, he unleashes his special attack: nothing. As in, he literally stands there doing nothing, refusing to allow you to take your turn, figuring that sooner or later you'll get bored and quit.]] The whole thing is probably best summed up with this one-liner:
-->'''Sans''': [[spoiler:huh. always wondered why people never use their strongest attack first.]]
* CoolBigBro: For as much he enjoys messing with him, Sans' relationship with Papyrus is remarkably strong. He's laid-back, quick with a joke, and appears to be very popular with the town residents, yet he still considers his dorky manchild of a little brother the coolest person he knows.
* DamageOverTime: [[spoiler:In addition to massive direct damage when you touch them, his attacks also leave a slow damage over time effect called Karmic Retribution. The more you get hit, the longer this effect lasts.]]
* DangerouslyGenreSavvy:
** Very much so. Pray he never shows you how much he understands how things work.
** [[spoiler: During a No Mercy run, he reveals that he's fully aware of your ability to save and reload the game, and the fact that you're slaughtering everyone more or less for your own amusement. Thus, his goal is not to just simply kill you, since you'll just keep trying until you beat him, his goal is to make his fight so frustrating and unfair that you (the player, not your character) simply RageQuit.]]
** [[spoiler: His "special attack" involves him literally doing nothing. He'll even repeatedly teleport you to the center of the bullet box ''just in case'' there is any possible funny business you can pull to try and escape; you have to wait until he's fallen asleep first before attempting to drag yourself over to the fight button. Even managing to do that is not enough due to Sans waking up to dodge and taunt just before you could strike him. He only goes down because you take your turn twice, catching him off guard with your second attack.]]
* DeadpanSnarker: When his humor isn't puns, pranks, or some combination of the two, it's this, and many of his lines are dripping with it. Especially in response to Papyrus.
--> '''Papyrus''': YOU'RE SO LAZY!! YOU WERE NAPPING ALL NIGHT!!\\
'''Sans''': i think that's called... sleeping.
* DeathByIrony: [[spoiler:Sans spends entire fight playing on your expectations and trying to catch you off guard. How do you defeat him? By catching ''him'' off guard with a surprise attack while he taunts you after pulling yet another NonchalantDodge.]]
** [[spoiler:He can also inflict this on you. Earlier, Papyrus spared you and offered a hug, only to be killed while his guard was down. Midway through the fight with Sans, he tries to spare you. If you accept his mercy, he also offers a hug, then kills you while you're off-guard.]]
* DeathOfAThousandCuts: [[spoiler:Basically his combat strategy. Individually, his attacks are the weakest in the game. But they also avoid triggering your MercyInvincibility, and he can attack ''a lot''.]]
* DemBones: He's a talking skeleton who loves to eat and sleep.
* DespairEventHorizon: He's goofy and a PungeonMaster, but underneath that big grin, Sans... Sans is not well. [[spoiler:Living with the knowledge that at any second your life can be irrevocably snatched away from you every minute of the day tends to do that to a guy.]]
* DeterminedDefeatist: When he decides to step in and take action [[spoiler: at the end of Genocide run, he’s pretty much resigned to [[HopelessBossFight his tragic fate]]. But knowing that you’re about to destroy the world...he just can’t afford to not care anymore. He gives the player one hell of a final fight with the hopes of anomaly (the player) to RageQuit but at the end of the day, you are too [[SaveScumming determined]] to give up and he knows it from beginning to end.]]
* DissonantSerenity: No matter how people react around him, Sans has the same big grin on. [[spoiler:This is implied to be an act, since he keeps this up even when it's clear he's in anguish or furious. He even keeps calm and casually talks about getting some food once he's mortally wounded.]]
* DoNotTauntCthulhu: [[spoiler: Alright Sans, pulling off a ISurrenderSuckers combined with ForgivenessRequiresDeath is legit. But did you really ''have'' to tell us to get dunked? Because that might have infuriated most to redouble their effort to take you down.]]
* TheDreaded: [[spoiler:Anybody who has caused enough destruction to invoke Sans' wrath learns to fear him. Flowey states in a post-Neutral conversation that Sans is the only thing that has kept him from reaching Asgore on his No Mercy runs, and he's had to reset multiple times to avoid him; the only time Flowey gets the better of him is in the True Pacifist run by catching him and everyone else off-guard. The Fallen Child, despite being an immoral, emotionless murderer, will [[OOCIsSeriousBusiness express concern]] only when they have to fight Sans.]]
* DrosteImage: He keeps a joke book in his and Papyrus' house which hides a Quantum Physics textbook, which hides another joke book, [[RunningGag which hides another Quantum Physics textbook.]] [[HiddenDepths Pretty good metaphor for Sans himself, actually.]]
* DumpStat: His [[spoiler: HP, Defense and Attack are all 1. He doesn't need the first two as he can dodge extremely well and would die anyway from a single hit by the No Mercy Run protagonist, and his attack of 1 still deals ScratchDamage... ''without triggering MercyInvincibility''.]]
* EstablishingCharacterMoment: Stalking the protagonist in the woods outside Snowdin, only to reveal himself with the line "don't you know how to greet a new pal?". His hand-whoopie cushion establishes him as a good-natured prankster and {{Troll}} who doesn't work hard at all.
* ExactWords:
** Seems to be fond of these, in keeping with his persona as a ruthless prankster: Sans never actually lies to you [[spoiler:during his boss battle]], even though the implication of his words and his actions don't line up. [[spoiler:When asking you to Spare him, he says it would "make his job a lot easier," which is technically true in that he proceeds to kill the player while they are off guard, and once you do Spare him, he responds that he "won't let this go to waste," which he also doesn't... it's just that what he isn't wasting is his chance to take you out cleanly.]]
** [[spoiler:If you CHECK him in battle, he is described as "The easiest enemy. Can only deal 1 damage." This is ''technically'' true in that he has the worst stats in the game (only one ATK, DEF and [[OneHitPointWonder HP]]). But he dodges all your attacks, and his rapid-fire attacks override MercyInvincibility and leave behind residual damage, meaning every frame that heart touches his bone attacks will drop your HP rapidly, one by one.]]
** Most infamously, [[spoiler: when he uses his 'special attack', he says 'here goes nothing.' What happens next is...[[ExactlyWhatItSaysOnTheTin literally nothing]]. As in Sans ''refuses'' to end his turn, since knowing that as long as you get a chance to make your next move, you will kill him. So he simply waits, hoping that you'll get so bored that you'll give up and quit. Sadly for Sans, [[InterfaceScrew you give him a taste of his own medicine...]]]]
** A lighter instance can be seen in a post-it note argument Papyrus has with him.
--->'''Papyrus:''' SANS! PLEASE PICK UP YOUR SOCK!\\
'''Sans:''' ok.\\
'''Papyrus:''' DON'T PUT IT BACK DOWN! MOVE IT!\\
'''Sans:''' ok.\\
'''Papyrus:''' YOU MOVED IT TWO INCHES! MOVE IT TO YOUR ROOM!\\
'''Sans:''' ok.\\
'''Papyrus:''' AND DON'T BRING IT BACK!\\
'''Sans:''' ok.\\
'''Papyrus:''' IT'S STILL HERE!\\
'''Sans:''' didn't you just say not to bring it back to my room?\\
'''Papyrus:''' FORGET IT!
** [[spoiler:"Song That Might Play When You Fight Sans" is a remix of "sans." The song that actually plays is "MEGALOVANIA". The former isn't even in the game files.]]
* ExposedToTheElements: Not nearly as much as his brother, but he's still wearing shorts and slippers ''in the snow''.
* FamousLastWords:
--> [[spoiler:"papyrus, do you want anything?"]]
* FatalFlaw: He is really, ''really'' lazy, even if the cause of that is up for debate. While it's played for laughs every time it comes up for the most part, [[spoiler:he winds up exhausted should the player make it all the way to the end of his final barrage in No Mercy. From there, he starts to doze off...]]
** When Sans unleashes his special attack, (which turns out to be prolonging his turn to get you to quit) the only way to beat him is to [[spoiler: drag the box you're in over to the 'FIGHT' option. The only hint you're given to do this? Any time you get too close to the lower left-hand corner, Sans' eye flashes blue, and you are thrown back to the center. His precaution is ultimately what causes his death.]]
* TheFatalist: His humorous facade hides a deep and bitter cynicism. He stopped caring a long time ago and prefers to observe, rather than act. [[spoiler:However, he eventually gets motivated to take a stand near the end of the No Mercy run, despite acknowledging that due to your ability to reset, it's impossible for him to really win. The most he can hope is to get you to RageQuit.]]
* FatAndSkinny: The fat to Papyrus' skinny. He's surprisingly stocky for a skeleton, considering he doesn't have any flesh to speak of. [[StealthPun Because he's not fat, he's big-boned.]]
* {{Foreshadowing}}: Despite Sans downplaying Papyrus's abilities, he's definitely no pushover. [[spoiler:Sans has pretty high standards when it comes to power.]]
** Happens even earlier on in an easily-missed moment. [[spoiler:When you first enter Snowdin, there's a large branch in the path that's "too heavy to move", implying that it's fairly large. Once Sans starts following you, if you backtrack a bit, you'll notice that the branch has been ''snapped in half''. Considering Sans and the Human Child are about the same size... WOW.]]
* FinalBoss: [[spoiler: Of the No Mercy route. After him, you move onto Asgore who's automatically one-shotted, so he's the last true boss you'll fight.]]
* FragileSpeedster: [[spoiler:Sans takes this trope to its absolute conclusion. He is a OneHitPointWonder, but good luck getting even one hit in.]]
* FullContactMagic: [[spoiler:In his boss fight, he slams your soul into the walls and ceiling of the action box with a wave of his hand.]]
* FunetikAksent: His "-ing" words usually end in an "-in'", he says "'em" instead of "them", and he occasionally strings words together like "forgeddaboudit" and "howzabout it". Since the game has no voice acting, fans typically interpret this as some variety of New York accent.
* ForgivenessRequiresDeath: If you accept his offer of friendship in No Mercy Run.
--> [[spoiler: If we're really friends.... you won't come back.]]
* GameFace: Sans is always grinning, constantly looking around to make aside glances while he talks, giving him a cheerful, animated feel. [[spoiler: When his eyes disappear and he just ''stares'' straight at you with empty, pitch-black eye sockets, you know things have just gotten real. And when his left eye starts [[GlowingEyesOfDoom glowing]]... start praying, for all the good it will do.]]
** On the flip side, [[spoiler:his eyelights also disappear at one point in a Pacifist run, when he tells you his secret secret codeword: "I'm the legendary fartmaster.", implying confiding such, to him, is SeriousBusiness.]]
* GlassCannon: [[spoiler: Sans when serious is raw annihilation incarnate, and perhaps even more dangerous than [[TrueFinalBoss Asriel]] himself. ...He is ''also'' more fragile than ''Whimsun''. Seriously, he has '''''1 HP'''''. A ''stiff breeze'' could knock him over. Thankfully for Sans he is plenty aware of this, and is an absolute master of the art of dodging.]]
* GlowingEyelightsOfUndeath: His general expressions have those. They actually help making him look friendly and approachable (probably because of the artstyle). [[spoiler:They will disappear when he wants to sound threatening]].
* GlowingEyesOfDoom: [[spoiler:One of Sans's eyes glows as he uses various abilities during his battle, like Asgore.]]
* GoddamnedBoss: InvokedTrope. [[spoiler:He knows that you can just use SaveScumming to keep trying until you take him down, so he deliberately makes his fight as frustrating as possible to make you RageQuit.]]
* GodzillaThreshold: In the No Mercy run, [[spoiler:that would be ''you'', and the reason that Sans decided to get off his ass and try to stop you with anything he could muster, before you poison every timeline in the game.]]
* GoOutWithASmile: In the Genocide run, [[spoiler:despite probably being in immense pain from being slashed across the torso, he still manages to keep smiling even as he dies.]]
* GroundhogDayLoop: [[spoiler:Sans compares you starting and restarting the timeline via saves as this in the Genocide path as you're fighting him. Part of his laziness is because he knows how futile everything would be if it all resets again.]]
** Implied that [[spoiler: he forced Flowey into this as well, as the latter remarks how much he hates Sans for the number of resets Sans caused him.]]
* HardWorkHardlyWorks: Papyrus constantly tries his best to join the Royal Guard while Sans just mostly slacks off. [[spoiler:Yet Sans is by far the strongest of the two brothers.]]
* HeavySleeper: Sans appears to be rather lazy and can be seen sleeping on his job once. [[spoiler:This proves to be his undoing on the No Mercy route.]]
* HeroAntagonist: In the Genocide run, [[spoiler:he's the last fight before Asgore and the only character besides Undyne to give you any trouble. The flavor text, music, and general atmosphere of the fight all emphasize how ''Sans'' is the last line of defense between you and destruction of his world, and how the player deserves everything that's being thrown at them.]]
* HeroicBSOD: If you kill Papyrus, regardless of how few others you kill, [[spoiler:Sans completely disappears from the game until his judgment. He cares a '''lot''' about his brother.]]
* HeroOfAnotherStory: [[spoiler: It plain as day once you've learned what he knows that before Frisk came around, Sans was the only one working behind the scenes trying to save the Underground. He's been keeping tabs on the activity of the timeline, has been working diligently on some kind of machine in the basement of his home, and he keeps tabs on virtually the entire Underground with a little help from his teleporting shortcuts. To top it off, when you face him in the Genocide battle, he can attack you at all times and avoid all attacks, almost as if ''he'' was the player character and ''you'' were the boss monster. If you complete a few neutral runs in a row, Flowey would tell you to steer clear of Sans, as he had barred Flowey's path multiple times before, and caused him to reset. [[OffscreenMomentOfAwesome Successfully.]]]]
* HiddenDepths: [[spoiler:Sans tends to [[AlmightyJanitor keep a low profile]], but displays awareness of his alternate selves, the multiple timelines and resets, praises you if you didn't die up to the restaurant scene, counts the number of times he kills you, possesses incredible time-space abilities similar to yours and owns items such as the group shot you get by clearing a Pacifist run and choosing not to stay with Toriel. Just what is his deal?]]
* HopelessBossFight: [[spoiler:The fight in the No Mercy run is this. Not for you, but for ''him''. While he can (and will) kill you very quickly and messily, he knows it won't do any good since you can just reload your save and try again, and it's only a matter of time before you finally defeat him. The best he can hope for is to try to get you to RageQuit from the difficulty.]]
* HorrifyingTheHorror: [[spoiler: Both [[BigBad Flowey]] and [[GreaterScopeVillain The Fallen Child]] dread the moment Sans gets serious.]]
-->'''Flowey:''' [[spoiler: Say, if I have ONE piece of advice for you... DON'T. Let (Sans). Find out ANYTHING about you. He'll... well... Let's just say. He's caused me more than my fair share of resets. Stay away from him.]]
-->[[spoiler: "You feel like you're going to have a bad time".]]
* HumansAreTheRealMonsters: Some dialogue with him implies a distrust of humanity that runs deep, in contrast with his brother, who would at least give a human caught wandering the Underworld a fighting chance. Sans reveals he's less lenient in that regard when he confides to the player late in a Pacifist run that [[spoiler:he would've killed you the moment he saw you if Toriel hadn't made him promise not to harm any humans he came across.]]
* HoistByHisOwnPetard: [[spoiler: After an entire fight of throwing InterfaceScrew after InterfaceScrew at you, you beat his 'special attack' - i.e. him refusing to make his next move so you can never take your turn - by breaking the interface yourself, allowing you to press the Attack button in spite of it not being your turn.]]
* HPToOne: [[spoiler:Karmic Retribution will never reduce your health to 0. Similarly, you can't be killed getting hit by the bones in the menu while you're taking your turn, and his penultimate attack when he's bashing you against the walls won't drop you below 1.]]
* TheHyena: His VoiceGrunting is a low-pitched chuckle. Hehehehehehe...
* HyperAwareness: Sans may be the 'laziest' monster you'll meet in the Underground, but he's highly attentive to detail, down to subtle facial expressions. He also makes it a point to know and speak to everyone, getting a reading on personalities. He knows [[spoiler: through a combination of science, guesswork, and observation that a time-space anomaly has been ongoing for some time]]. It's implied that he's a competent tracker, should he stay awake long enough to do his job as a sentry.
* IconicOutfit: His hoodie/sport shorts/slippers combo.
* IGaveMyWord: Sans hates making promises, but if you can get him to make one, you bet your life he'll keep it. Case in point: you can ruthlessly slaughter just about anybody you want in the underground, up to and including his own brother, and despite the pain it clearly causes him, [[spoiler:he ''still'' won't break the promise he made to Toriel to keep you safe. Only once you're at the end of a genocide route and he knows for sure that you're going to destroy ''[[OmnicidalManiac everybody]]'' [[OmnicidalManiac and]] ''[[OmnicidalManiac everything]]'' if he lets you live does he finally set this commitment aside to try and stop you, and even then, the last thing he does before attacking you is apologize to her for it.]] This decision is somewhat justified, however, since [[spoiler:he's aware of your ability to reset the game, so he knows that you're more than likely going to start over shortly after you finish and everything will be back to normal. It's only on a genocide route that everything gets destroyed ''permanently'', hence him breaking the promise.]]
* IKnowYoureInThereSomewhereFight: [[spoiler: Sans' comments at the midway point of his boss fight has him call out to "someone who wanted to do the right thing", followed by a plea for them to let it end and reset. It's not made clear if he can remember a previous Pacifist run, can sense Frisk's kind heart beneath the OmnicidalManiac the Fallen is, or if he's simply bluffing, but it's clear he knows this ''isn't'' how it's suppose to be, and he's trying to get Frisk to realize that too. Unfortunately, Frisk is either [[LossOfIdentity completely gone]] or [[AndIMustScream still can't break free of your control]], so the effectiveness of this plea comes down to it reaching the player, not Frisk.]]
* InterfaceScrew: [[spoiler:Many of Sans' attacks abruptly change from one to the next, and during your turns he'll send bones through the menu to hit your SOUL cursor. He's able to change the direction of gravity during the Blue Heart phases as well]].
* IntergenerationalFriendship: With Toriel, as both of them really enjoy bad jokes. [[spoiler: Thanks to that, Sans didn't kill off Frisk the first time they met.]]
* IronicEcho: [[spoiler:Papyrus insists, in a Genocide playthrough, that anyone can be a good person if they try. Before fighting Sans, he asks you if you think "anyone can be a good person if they just try" before asking if you wanna have a bad time.]]
* ISurrenderSuckers: [[spoiler:Do you enjoy sparing people only to kill them when their guard is down? Well, if you think Sans is being sincere when he offers a truce to a mass murderer like you... [[KarmicDeath prepare to get dunked on.]] Besides just slashing him again, there's something that first-timers can look out for to realize he's faking. Remember how when enemies are in the sparing range, their names turn yellow? Sans' name does... but the "spare" option, which normally does as well, does not.]]
* IWarnedYou: [[spoiler: After you cut him down, before he stumbles offscreen and dies, he gives a defeated "welp, i warned you." He's very aware what's about to happen if you continue through the next two rooms and finish the playthrough, but it's no longer in his hands.]]
* IWillFightNoMoreForever: [[spoiler: With the little info on his backstory, the only clear part is that Sans wasn't always a "lazybones". For a long time he did his best to "fix" the broken machine in his basement; possibly to bring back people he lost and by extension, to get to the surface. Unfortunately the machine can not be fixed according to WordOfGod and Sans has no power to stop the resets. By the time you meet him, he's already resigned to [[EternalRecurrance his fate]] and doesn't care about going to surface or seeing his lost loved ones anymore.]]
* LaserGuidedKarma: [[spoiler:While fighting him, your life bar is under a "KR" effect that slowly decreases your HP like poison every time Sans hits you. Given cut battle narration lines in the script stating you're doomed by KARMA, it's safe to assume KR stands for Karmic Retribution. He also attempts to kill you by feigning a truce, much like you easily could have done for Toriel and many ordinary monsters at this point.]]
-->[[spoiler:''"You feel your sins crawling on your back."'']]
* LastStand: [[spoiler: His boss fight. Sans knows that your power to reset means that he can't beat you. But after seeing all the death left in your wake, knowing that you'll go on to destroy other timelines, and that there's no one else who can fight you, he decides he can't afford to not care anymore. Sadly, despite his best efforts to get you to give up, his laziness ends up costs him his life.]]
* LeaningOnTheFourthWall: More than a bit MediumAware. [[spoiler:He uses this to full effect when denying you your turn in the battle against him, thus denying you the ability to actually progress through the game. Also extended to how he treats your reloads, which he seems to observe from an in-universe perspective. While Flowey is actively aware of how you handle the timeline and abuses savestates to skip around, Sans seems to treat your different loads as alternate timelines and simply skips forwards in battle without any visible justification. The main method of figuring out you've reloaded? Not through hard evidence, but simply recognizing how you react to different things. "That look on your face...it means something."]]
* {{Leitmotif}}: The appropriately titled "sans." is a laid-back, quirky theme that suits him well. The song that plays when you have dinner with him is a remix of this song
* LethalJokeCharacter: [[spoiler:Sans is described as the easiest enemy who can do only a single point of damage per hit. As it turns out, what this really means is 1 ATK ''per frame''. And boy, does he take advantage of this to the extreme. Not only does he attack at ridiculous rates and in ridiculous amounts, but also, the 1 ATK means his attacks pierce MercyInvincibility to deal constant damage and leaving a poison effect. And they're some of the most ''intense'' in the entire game, because of the speed and range of his attacks (in some cases, there's literally just one tiny spot in the box where you can hide). He leaves the 1 defense point moot by constantly dodging your one hit kill swings.]]
* LetsGetDangerous: [[spoiler:In the No Mercy run, he comes to realize he can't stand by anymore, and resolves to finally do his job.]]
--> [[spoiler:all i know is...seeing what comes next...i can't afford not to care anymore.]]
* LosingHorns: When the Annoying Dog eats Papyrus' stash of bones and gets away, Sans peeks out of his room and plays a few mocking notes on a trombone.
* MagicFromTechnology: While he does have powers similar to Papyrus, Sans doesn't have [[spoiler:the power to SAVE or RippleEffectProofMemory]]. He shows that he can make up for it with a scientific background and, [[GuideDangIt if you can figure out how to access it]], [[spoiler:what is heavily implied to be a broken time machine in the locked room behind his house]].
* ManOfAThousandVoices. InUniverse example. He does a pretty good Toriel impression, insofar as you can tell from the sound of text scrolling.
* MarathonBoss: [[spoiler:Yes, he only has 1 HP. But you're faced to waste 22 turns just to try and get a chance to hit him, not including turns to stop to heal.]]
* MeaningfulName:
** He has a very comical personality, and [[PaintingTheMedium His speech is written]] in Comic Sans. He's also very lazy, and Comic Sans is often seen as a lazy choice. [[spoiler:Except when he's being serious, where it changes to a more conventional, "serious" sans-serif font (8bitoperator).]]
** "Sans" on its own means "without" or "lacking". [[spoiler:Which fits his hopeless view on the world, poor Sans is lacking in a lot of things.]]
** [[spoiler: Fans have taken this to mean all sorts of things. Sans, of course, is obviously a negation, but 'Serif' sounds like 'seraph', the angelic host, and something which a prophecy in the game predicted would appear -- an angel from the surface, guaranteed to remove everyone from the Underground.]]
** Averted for his battle theme, "Song That Might Play When You Fight Sans". [[spoiler: It doesn't play. "MEGALOVANIA" is his battle theme, but Sans isn't a megalomaniac. By that point, the psychotic power-hungry maniac is YOU.]]
* MediumAwareness: Sometimes displays this as part of a gag. [[spoiler: He knows MUCH more than he lets on, for instance, he's aware that the player can save and reset events at will. He's also aware of how battle structure works and tries defeating you by prolonging his turn, denying you your turn.]]
* MetaphoricallyTrue: [[spoiler:His stat readout lists him at 1 attack and 1 HP. And while that is technically true, he not only ''refuses'' to let your attacks land, but his attacks continually deal 1 HP for every instant their hitboxes make contact with you ''and'' apply a poison effect that ticks down at - you guessed it - 1 damage a second.]]
* MindOverMatter: [[spoiler:His ability to slam the your character's SOUL against the inside of the battle box via hand motions seems to suggest he can do this.]]
* MouthFlaps: Averted. Sans noticeably never seems to opens his mouth to talk.
* MysteriousPast: Oh, absolutely. The game has deliberately-placed hints about his prior life littered throughout it, all of them vague but heavy in their implication. There's a reason he and [[spoiler:his relative/friend/co-worker/''something'' W.D Gaster]] have spawned more speculative fan material than any other characters.
* MundaneUtility: [[spoiler:Uses both his time manipulation and his incredible guesswork to set up a prank that transcends time. And according to Papyrus, he does things like this frequently.]] He also teleports himself and friends anywhere and everywhere for any reason, the most common reason being "a cheap joke".
* MyFriendsAndZoidberg: [[spoiler:A schedule of events can be found at the MTT Resort advertising "performers, comedians, and Sans."]]
* NiceGuy: [[SurpriseCreepy Occasional creepy moments aside]], he's very friendly and always treats the player like an old buddy, even after they just met. [[spoiler:Makes sense after all, he's well aware that this most likely is not the first time he's met the player; him befriending them is his way to make a potentially genocidal player think twice about going through with it. He has his limits, however: kill his brother and he'll want nothing to do with the player, only appearing again to tell them off at the end of the game. Probably the only reason why he doesn't make them [[SNKBoss have a bad time]] then and there after killing Papyrus out of rage is because the player can still reset the timeline, thus undoing his battle/murder.]]
* NonchalantDodge: [[spoiler:Sans can sidestep your attacks. [[LampshadeHanging Well, why doesn't anyone else?]] ...But then it's subverted to disturbing effect when the player character spams the attack button [[DiagonalCut and slices him in two.]]]]
* NoNonsenseNemesis: [[spoiler: Granted, it takes ''a lot'' to push Sans into dropping the nonsense and becoming your nemesis, and even that is ''only'' because he made a promise to Toriel, but once you've crossed the final line of no return and there are no other options left, he'll cut out the puns and... well, the CombatPragmatist section up there can tell you all about it... "You feel like you're going to have a bad time" ''indeed''.]]
* OffscreenTeleportation: Sans can warp around when out of sight and often shows up way ahead of you through the areas [[TookAShortcut for no explained reason.]] [[spoiler:The abilities he displays during his battle suggest he has some control over time and space like you and Flowey do.]]
** Subverted for once in Genocide Route. [[spoiler: He tells you that you will have a bad time if you continue, then the screen blinks, and he's gone.]] It makes for a very creepy moment.
* OhCrap: His expression just before [[spoiler:he is sliced in half.]]
* OlderThanTheyLook: His age is extremely vague, but he's clearly an adult. Despite this, his overworld sprite is almost eye-to-eye with the player character's, and his presumably more-proportionate battle sprite is still squat enough to give the impression that he's a child.
* OneHitKO: [[spoiler:Partway through the fight, Sans will offer to spare you. This is a trap; if you accept this offer, Sans will fill up the combat box with bones arranged in a jail-cell pattern that ''can't be dodged'', taking off all your health and resulting in a game over.]]
* OneHitpointWonder: [[spoiler: Sans has one HP, but he is still the hardest boss in the game.[[note]]In practice, he has 22 HP, because his script only advances when you attack him. I.E. to get to his "special attack" (whereupon you can end the battle) you need to attack him 22 times.[[/note]]]]
* OOCIsSeriousBusiness: Sans is almost always cracking wise or lazing about, seemingly without a care in the world. Yet he has his moments of gravity, and when it comes time to deliver them, [[GameFace his pupils fade into darkness]], his VoiceGrunting disappears (often taking the background music with it), and he loses his AllLowercaseLetters speaking style. He even changes fonts (he usually speaks in Comic Sans, but switches to the sans-serif 8bitoperator for his serious lines). Also, if it's your fault that Sans finally decides to [[LetsGetDangerous stop being lazy]], well... [[ThisIsGonnaSuck you're gonna have a bad time.]]
* PaintingTheMedium: To start, Sans speaks in comic sans. Secondly, he spends most of the game talking in AllLowercaseLetters... but at random he'll leave his I's capitalized, and he will sometimes use apostrophes correctly but sometimes won't. Yes, Sans is so lazy he can't even use AllLowercaseLetters consistently. Or to put it another way, Sans speaks like he's ''typing'' but is too lazy to type properly; now remember that Toby Fox had to type all of Sans' dialogue.
* PerpetualSmiler: Sans always has a mysterious smug, sneaky air about him, at least [[spoiler:when he's not exuding a TranquilFury attitude]] instead. Even when his eyes are giving away a different emotion, his giant grin never moves, most likely because he's a [[DemBones skeleton.]] The closest his grin ever changes is [[spoiler: when your blow finally connects,]] and even then it's just barely.
* PintsizedPowerhouse: would fit as a trope image just fine.
* PlatformHell: [[spoiler: Most of his attacks are done while your heart is Blue; they're fast, tricky to dodge, and deal a crapload of damage.]]
* ThePrankster: Not only does Sans love bad jokes and puns, he also likes to pull harmless pranks on the protagonist. Whoopie cushions in the hand and on the chair, loosening the cap on a ketchup bottle and having paint in a telescope's eyepiece stand out.
* PreAssKickingOneliner: [[spoiler:"it's a beautiful day outside. birds are singing, flowers are blooming... on days like these, kids like you... '''Should be burning in hell.'''" This is even played with to mess with you even further - he'll cut the speech off mid-sentence and immediately jump into his opening routine entirely at random.]]
* PungeonMaster: Sans enjoys harassing Papyrus with bad skeleton-related puns.
* RealityWarper: Very much so. If you also survive his penultimate attack, ''he flips out'', and starts throwing you around everywhere, in what truly is the only unavoidable attack in the entire bullet-hell game.
* TheReasonYouSuckSpeech: [[spoiler:Delivers one to the player in the second stage of his battle, questioning why they want to destroy his world so badly. Given that this happens after his attempts to stop the player through trickery and just plain making the battle difficult have failed, doubles as an attempt to BreakThemByTalking.]]
--> [[spoiler:i always thought the anomaly was doing this cause they were unhappy. and when they got what they wanted, they would stop all this... but that's ridiculous, right? yeah, you're the type of person who won't EVER be happy.]]
* RedOniBlueOni: The blue to Papyrus' red (blue clothing, calm personality...).
* RhetoricalQuestionBlunder: Meta-wise. Do you feel bad for killing Papyrus? Invoke WellIntentionedExtremist, and you can do just that without feeling awful.
-->'''Sans:''' Then why did you kill my brother?\\
[[spoiler: '''You:''' This is for the best.]]\\
'''Sans, later on:''' [[spoiler: This is the best life. Thanks.]]
* RoaringRampageOfRevenge: [[spoiler: He ''unleashes hell on you'' for all the innocent lives you've taken, and if you went and killed Papyrus as well, he's already let you know before this that you've well and broken his last straw.]]
* SadClown:
** [[spoiler:Alluded to when facing him as a Lost Soul, and explicitly stated when fighting him on a No Mercy run. His knowledge of the player's and Flowey's interference with the timeline (through saving and resetting), and the belief that things will inevitably be reset again in the future, has left him exhausted and existentially depressed. It's implied that this also has something to do with W.D. Gaster and the strange machine Sans is working on...]]
** Sans also displays a degree of self-loathing, most notably in the ending where [[spoiler: you kill all of the important characters, leaving the Underground utterly bereft of leaders. Sans talks about why he didn't take up the throne and explains that it isn't his style, and that he prefers to take things easy... before explaining that that was a joke and the whole mess they're stuck in is exactly what happens when "people like [him]" take it easy.]]
* SealedEvilInADuel: [[spoiler: Attempted. His 'Special Attack' is simply to start his turn... and never end it. He outright says that he intends to just sit there until you get bored and turn off the game. Unfortunately, he falls asleep after a while, allowing you to kill him anyways.]]
* SeriesMascot: While Flowey has been pushed to being one, Sans has a lot of icon power on the internet to the point where people who have only glanced at Undertale but never played it can probably recognize what game he's from when they see him elsewhere. Tends to happen when you're one of the most liked characters [[spoiler: and a freakishly difficult and memorable BonusBoss, which is verging on ItWasHisSled in most circles.]]
* SetRightWhatOnceWentWrong: [[spoiler:A photograph in Sans' room reveals that there was once a timeline where Sans was surrounded by friends "you don't recognize". Between his comments that he, "gave up trying to go back a long time ago" and Flowey talking about how many resets Sans has cost him, it's fair to assume Sans spent a ''lot'' of time trying to undo a particularly heartless edit to the timeline]].
* ScrewTheRulesImDoingWhatsRight: [[spoiler: When facing him at the end of a No Mercy Run, he disregards many of the established mechanics in the game and fights dirty - interrupting his dialog to open with a brutal first strike, ignoring MercyInvincibility with his attacks, dodging your swings, feigning surrender, attacking while you're in the menu, and using his last turn to bore you into submission. All as a last ditch effort to stop you from killing everyone.]]
* SheatheYourSword: [[spoiler:What his special attack turns out to be -- he just never ends his turn, meaning ''you'' never get ''yours'', unless you find a way to cheat the system.]]
* TheSlacker: Sans takes laziness to an art form. At one point he converts a guard booth into a makeshift shop to hawk food to passersby. As an impressed Papyrus notes, he's not doing his job by ''doing another job.''
* SmugSuper: Sans definitely doesn't understate his own power when pushed far enough to use it. [[spoiler: In the No Mercy run, if the player loses to him (and they will - a LOT), he'll keep rubbing it in their face the first twelve times after reloading a save. Afterwards, he'll ditch the showing-off, and go straight into obliteration mode.]]
-->'''Sans:''' [[spoiler: do you wanna have a bad time? 'cause if you take another step forward...you are REALLY not going to like what happens next.]]
-->'''Sans [[spoiler: (After losing against him for the first time):]]''' [[spoiler: you look frustrated about something. guess i'm pretty good at my job, huh?]]
* SNKBoss: [[spoiler: A non-fighting game example. He breaks damn near every rule of the game (and of turn-based [=RPGs=] in general) when fighting you and is far and away the hardest fight in the game to boot.]]
* SoundOnlyDeath: Sans is the only [[spoiler:character you can kill that you don't get to see die onscreen. After you deliver the final blow, he resigns to his fate, then shuffles offscreen. Seconds later, you hear the "monster turns to dust" sound.]]
* TheSouthpaw: Close observation suggests that Sans is a lefty: he offers his left hand to shake hands at the start of the game, and at Grillby's he uses his left hand when he chugs an entire bottle of ketchup. [[spoiler:He also uses his left hand to smear you across the walls, floor, and ceiling with the gravity power of the Blue SOUL attack if you face him on a No Mercy run.]]
* TheSpook: Apparently he and his brother just sort of showed up in Snowdin one day. With Papyrus, it's less apparent, since he wears his heart on his shoulder, but Sans keeps most people at an arm's length, and it's never made explicitly clear just how much he knows about (or is involved in) any given plot point, though it's at least a fair bet to say "significantly."
* StandardStatusEffects: [[spoiler:Karmic Retribution has a damage-over-time effect, similar to a poison/bleeding effect. The more you've been hit, the more damage you take from it.]]
* StepfordSmiler: To varying degrees, depending on how the player affects the world and how hopeful things seem. [[spoiler:Even on the best possible path, he has enough awareness of just how easily things can be turned back that it's very likely a contributor to his lazy demeanor.]]
* StoppedCaring: He doesn't seem to care about anything aside from bad jokes and his brother. [[spoiler:He's figured out that someone or something has been resetting and manipulating the timeline, and has given up trying to stop them... aside from befriending everyone he meets in the hope that one of them is the source, and he can finally make them happy]].
* StrongerSibling: [[spoiler:His brother Papyrus is a BadAss of his own right... But Sans is far, far more powerful than him. One shudders to think what would happen if he actually trained.]]
* TacticalSuicideBoss: [[spoiler: There's always a way to dodge his attacks, allowing you to weather his barrages and exhaust him. But he's shown capable to perform inescapable attacks too, so there's really no reason why he'd provide platforms for you to survive his attacks other than [[{{Unwinnable}} a purely gameplay perspective.]]]]
* TalkToTheFist: [[spoiler: He's the only enemy in the game who gets the first turn in combat, very likely catching you off-guard. And if you think you can try skipping his intro speech, [[BeCarefulWhatYouWishFor he'll gladly oblige]] and cut off his speech abruptly straight into his opening barrage.]]
* TeleportSpam: [[spoiler: Sans can bend time and space to a degree, and he abuses this ''liberally''. The entire game he teleports his sentry station from Snowdin around as a hot dog stand (you can even see the snow still on the roof, and a monster comments on that) and he repeatedly takes "shortcuts" by walking in the ''complete opposite direction'' of his destination and [[OffscreenTeleportation arriving there in-between screen transitions]], anyways.]]
* ThisIsGonnaSuck: [[spoiler:If you survive his opening barrage in the boss fight, he immediately opens his eyelights again and says "here we go"]].
--> [[spoiler:''"You feel like you're going to have a bad time."'']]
* TooDumbToLive: [[spoiler:When fighting him on the Genocide Route, he knows full well that you're a time-warping unkillable demigod, and his strategy is not to kill you, since he knows that's impossible, but rather to annoy the shit out of you until you RageQuit, thereby saving the world from you. Sound enough strategy. But the problem is that if you defeat him and then spare him... he'll stab you in the back and kill you despite the possibility that your mercy was genuine, thereby guaranteeing that you will try to kill him next time you fight, a fight you just established you're capable of winning.]] To be fair, [[spoiler:he does tell you what to do on the game over screen if your mercy was indeed genuine; quit the game and reset.]]
* TrademarkFavoriteFood: He seems to like to drink condiments like ketchup like a beverage.
* TranquilFury: Sans, of course, is a very chill skeleton...[[spoiler:and the most chilling thing about him is his no-nonsense font and lightless sockets if you manage to piss him off.]] Taken UpToEleven during [[spoiler:the final battle with him, where he's ''still'' grinning with one hand in his pocket as he ''pulverizes'' you with the other one, one of his eyes literally flashing with rage.]]
* TrashOfTheTitans: [[spoiler:His room turns out to have a literal trash storm in it]].
* {{Troll}}: It's pretty much his M.O. One of the best (and arguably most hilarious) instances of this is during [[spoiler: his boss fight, should you accept his offer of mercy (and get hit with the subsequent - and completely unavoidable - OneHitKill attack).]] The "Game Over" music will be replaced with a sped-up version of the goofy "Dog Song" track as Sans mocks you. Reload the game and talk to him again and he'll mention how incredibly pissed off you look.
-->'''Sans:''' geeettttttt dunked on!!
* TrustPassword: [[spoiler:If you reload a save after listening to his Judgment during a Pacifist run, he will give you one of these that, if you reset and talk to him again, will utterly fail to convince him that you're a time traveller. He will, however, give you a ''second'' password that, when reset and told to him again, causes him to give you a key to his room. The passwords are, respectively, [[{{Troll}} "I'm a stupid doodoo butt" and "I'm the legendary fartmaster."]]]]
* TurnsRed: [[spoiler:While other bosses get gradually more difficult, Sans does his difficulty spike all at once. Once you reject his offer of mercy, he'll step up his game. This is the part where he outright starts cheating, unleashing combos that require you to do different things and attacking you while it's your turn.]]'
* UnexplainedAccent: As mentioned above, he seems to have some variety of New Yorkian accent. Pretty weird coming from a guy who's spent his entire life underground among monsters who mostly lack readable accents, especially since his own ''brother'' doesn't even have one.
* VideoGameCrueltyPunishment: He will judge you near the end of your journey, and he has some [[PlayerPunch choice words]] should you engage in VideoGameCrueltyPotential. [[spoiler: And if you've been going for the KillEmAll route, he bars your path as ''the'' single toughest boss in the game.]]
* VitriolicBestBuds: He deliberately annoys his brother Papyrus almost every second they're on screen together, who constantly nags and complains about him back, but it's always in good nature and they're nothing if not completely dedicated to each other. Sans even mentions in an optional piece of dialogue that he appreciates Papyrus' nagging, since it's the only thing that [[TheSlacker actually motivates him to do anything productive]].
* WalkingSpoiler: There's quite a bit more to Sans than just the joke-loving skeleton you meet early on. Those avoiding spoilers take heed: even glancing at fanart of Sans gives away a lot about his character.
* WaveMotionGun: [[spoiler: His "Gaster Blasters", which are skull-like cannons that fire off massive beams in a straight line with little to no time spent to let you get a sense for their angle. Sans is capable of summoning multiples at once at varying sizes and patterns to catch you out, they're easily one of his hardest to dodge attacks, and given the entire fight is ridiculously hard, that says something.]]
* WeakButSkilled: [[spoiler:Technically speaking, he really is the weakest enemy in the game, having only 1 HP and only capable of doing 1 damage. He makes up for it through clever abuse of game mechanics. He only has 1 HP, but he dodges all of your attacks instead of just taking them like every other monster in the game. He knows 1-damage attacks don't trigger the invincibility period, so he does 1 damage ''per frame''. That's not even getting into his SPARE trick, or his "special attack". Indeed, the only reason you can even kill him is by breaking the game -- dragging your SOUL over to the ATTACK button ''during his turn.'']]
* WideEyesAndShrunkenIrises: [[spoiler:The lights in his eyes become very small pinpricks of white after you mortally wound him.]]
* WhamLine: Sans has several which are said WITHOUT his usual 'accent' of Comic Sans, such as...
--> [[spoiler:''"You'd be dead where you stand."'' - referencing that if Toriel hadn't asked him to leave you be, he would've instantly killed you the moment he saw you.]]
--> [[spoiler:''"LOVE, too, is an acronym."'' - Near the end, the not-so-goofy Sans reveals the true nature of your stats and judges your actions.]]
--> [[spoiler:''"You dirty brother killer."'' - Only said if you kill Papyrus but aren't on a No Mercy run.]]
--> [[spoiler:''"If you keep going the way you are now... you're gonna have a bad time."'' - Said on the No Mercy run, in place of what was previously innocuous advice about the upcoming boss battle. He teleports away immediately after, which is also the only time in the game you actually ''see'' him teleport, with a very creepy effect.]]
--> ''"What? You think I'm just gonna stand there and take it?"'' [[spoiler: Upon dodging the one-hit kill strike that felled so many bosses beforehand.]]
* WorldsBestWarrior: [[spoiler: There is not a soul in the Underground more deadly than the short, goofy pun-lover. Sure, he might be the physically weakest monster there, but he'll essentially break reality to take you down.]]
* WouldHurtAChild: Claims he would've killed you the moment he first saw you were it not for [[spoiler: his promise to Toriel]], and on a No Mercy/No Mercy run [[spoiler: he actually does it (or tries to, anyway.)]]
--> '''Sans:''' it's a beautiful day outside. birds are singing, flowers are blooming. on days like these, kids like you...[[spoiler: '''Should be burning in hell.''']]
* YankTheDogsChain: [[spoiler:If the player's earned the True Ending, in subsequent play-throughs he'll have a copy of the group photograph that you're given where you choose to not stay with Toriel. The fact that he has it means that he's at least aware of the True Ending where everyone gets to survive and reach the surface... and then seen all that undone.]]
* YouBastard: [[spoiler: If the player kills Papyrus on a Neutral run they will get called out by Sans as a "DIRTY BROTHER KILLER."]]
* YouCannotGraspTheTrueForm: He has the ability to [[spoiler:attack you ''in between turns'' by hitting your menu cursor.]] One can only imagine what an attack like that would translate to in-universe...
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