Undertale - Other Characters / Characters

Undertale Main Character Index
Major (The Human Child, Flowey, Sans, Papyrus, Undyne, Mettaton, Asgore Dreemurr)
Others | Monsters | Spoilers (The Fallen Human)

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Mini-bosses

Napstablook

https://static.tvtropes.org/pmwiki/pub/images/image17.png

"i'd just weigh you down."

A humourless ghost monster who is good at pretending to sleep and sound mixing.

Accidental Hero: Napstablook comes in to break up the stalemate between you and the Mad Dummy... if only by complete accident. Later on, their call to Mettaton inadvertently convinces him that you shouldn't be killed.
Achievements in Ignorance: In the True Pacifist ending, it's revealed that they escaped Asriel/Flowey's absorbing of every monster soul in the Underground simply by closing their blinds.
Affectionate Nickname: Their cousin Mettaton calls them "Blooky."
all lowercase letters: Napstablook's lines are always written in lowercase letters, with no punctuation other than a miserable set of ellipsis at the end of a sentence... Like the Skeleton brothers, their lowercase contrasts with Mettaton, who usually speaks in CAPS LOCK.
Ambiguous Gender: Only called "they" by other characters, even in their cousin's diaries. Toby Fox did refer to them as "he" once in the original version of the art book, but this was edited after a fan backlash.
Apologetic Attacker: Napstablook inverts this trope, as they apologize for not attacking you, due to them "really not feeling up to it right now."
Apologises a Lot: When they feel like they've inconvenienced you, which is a lot of the time.
Grey Attack: Really not feeling up to it right now. Sorry.
Bedsheet Ghost: In terms of appearance, since they have no feet and resembles a sad Pac-Man ghost. Amusingly, Naptsablook is described as an actual ghost monster, meaning that their visible form looks like a stereotypical ghost because that's just how monster ghosts look.
Break the Cutie: If Mettaton's diaries are any indication, they've been depressive since their cousin decided to leave the Snail Farm to become a training dummy. Made even worse for them when Mettaton leaves the farm to become a celebrity. Tellingly, the player is the only person who is willing to be friends with them. (Undyne tried, but her Hot-Blooded personality was, by her own admission, a bit too much for Napstablook.)
Catching Some Z's: Napstablook repeatedly says "z" over and over to make you leave them alone. It doesn't work. The characters do all genuinely go "zzzz" when they sleep, though. The joke is that in Napstablook's case, the textbox spells out that the ghost is literally saying "z" instead of acting believably asleep.
Chekhov's Gunman: They start out as a simple random mini-boss, and completely leaves the story after that. Until they end up saving you from the Mad Dummy. Later on, they also accidentally help you Spare Mettaton, and turns out to have a major connection to him.
The Eeyore: Unless the protagonist makes an effort to cheer them up. And even then, it doesn't last long. They're generally in an endless downer mood, to the point their favorite activity after meals is to just flop on the floor and feel like trash for hours.
Foreshadowing: If you try to kill them, they don't flinch upon taking an attack. Continue to attack, and they reveal that ghosts can't be killed that way, and they were only lowering their HP to be polite.
Headphones Equal Isolation: Wears big blocky headphones while composing, which pull double duty as an excuse for them to not have to talk to people.
Hidden Depths: If the protagonist flirts with Napstablook in response to their 'Dapper-Blook' trick, their only response is "oh no...", implying that either Napstablook thought their attempt to amuse the Human Child went a little too well, or that they're slightly uncomfortable with being flirted with.
Leitmotif: "Ghost Fight", which later gets downplayed into "Pathetic House" when you meet up with them again later.
Medium Awareness: They're able to read the in-battle menu boxes, as shown if you Check them.
Check Description: This monster doesn't seem to have a sense of humor...
Napstablook: oh, i'm REAL funny.
Mini-Boss: They block the player's progress forward, and engaging them in battle is the only way to get past… unless you're on the "No Mercy" route, in which case they'll immediately disappear.
Nice Guy: A bit overly-passive and gets in your way briefly, but all in all, they're very friendly and inviting. And when you try to kill them, even though you can't? They lower their HP on purpose just to be polite.
Nigh-Invulnerability: Because they're incorporeal, they can only ever be harmed because they lower their own health bar in order to be polite.
No-Sell:
- If you try to kill them, they reveal that they're completely immune to your attacks and were only lowering their own health bar to be polite.
- When Flowey absorbs the souls of the entire monster population to become Asriel, Napstablook just closes the blinds of their windows to avoid the large flash of light outside and keeps themself busy with music.
Not So Harmless: If you cheer Napstablook up until they display their "dapper blook" look, but then fail to cheer them up again (flirting with them does much the same thing as cheering them up in this case, changing only their immediate reaction), they burst into tears and start unleashing barrages of projectiles that could put Touhou Project bosses to shame. Do not upset Napstablook, it'll be the last thing you do. They're also completely unkillable.
Ocular Gushers: They weaponize this as they attack the human by profoundly crying waves of tears.
Punny Name:
- Napstablook sounds a lot like "naps to block", which is exactly what they do in the Ruins.
- Their name also sounds like Napster, an old file sharing program. They're later revealed to be a DJ who uses another file sharing program to download music.
Red Oni, Blue Oni: They are the Blue oni to their disappeared cousin's Red. Napstablook is shy, overly polite, and self-deprecative; through their diaries, their cousin is shown to have a social life, use more casual language and criticize people, and put themselves first when given an opportunity to follow their dreams.
Secret Art: Uses a special "attack" that creates decorative grey images that deal absolutely no damage. The fact that Mettaton EX uses this type of attack for "HAPPY BREAKTIME" foreshadows his true identity.
Shrinking Violet: Napstablook is quiet, shy, socially awkward, and overly polite.
Skippable Boss: On the No Mercy path, if you exhaust your kill counter in the ruins before encountering them, Napstablook fades away as you approach their sleeping spot.
Sleepy Enemy: Parodied and (unsuccessfully) Exploited. Napstablook feigns sleep when you first encounter them, but they're really just trying to avoid attention by saying the letter "Z" repeatedly. Besides which, Blooky couldn't be anyone's enemy if they tried.
Slept Through the Apocalypse: When Flowey absorbs the soul of every monster, Napstablook doesn't even realize anything happened since they were at home with their blinds closed.
Spanner in the Works: When Mad Dummy realizes you can't hurt it and it can't hurt you, it decides to keep you in the fight forever by refusing to do anything during its turn. Napstablook unknowingly halts the battle by coming in to say hi and driving Mad Dummy away with their tears.
Swiss-Army Tears: They can both attack and form clothing with their tears.
Throw the Dog a Bone: In the True Pacifist ending, Mettaton decides to induct Napstablook into his new troupe, reuniting the cousins and letting them reach fame on the surface together.
Turns Red: If you don't cheer them up or flirt with them after they display their "dapper blook" look, their attacks get absolutely brutal and borderline undodgeable.
Villain Forgot to Level Grind: They're exactly the same on Hard Mode as they are in a normal game, despite almost everything else being stronger. Apparently, they "missed the memo and is the same difficulty as normal", as Check tells you.
Warm-Up Boss: Napstablook is the first enemy in the game whose attack patterns are legitimately hard to dodge even if you know what you're doing… but the pacifist way to beat them is very obvious, and if you do it right they'll only actually attack you for one round (being scripted not to attack on the second round of the fight or the turn before it ends). Also, they're a lesson about how bosses are harder to Spare than enemies are, while still being unkillable so you don't mess up a Pacifist run against them if you can't figure it out; no other boss except the Mad Dummy lets you off easy like that.

Snowdin Canine Unit

https://static.tvtropes.org/pmwiki/pub/images/dogs2.png

♥ * Pet

Doggo, Lesser Dog, Greater Dog, Dogamy, and Dogaressa (the latter two often being called the "Dogi"). A series of armored dogs guarding the path from the Ruins to Snowdin.

Achievements in Ignorance: Lesser Dog can be found at Grillby's playing a game of Poker against itself. And losing. By the Playable Epilogue, it finally manages to beat itself.
Admiring the Abomination: In the True Pacifist Ending, Doggo has no problems at all with his long-lost relative. Said relative is Endogeny, who is more or less an undead blob monster, and Doggo's happy that he can see it since it's constantly moving.
Ambiguous Gender: Lesser Dog is only ever referred to by "they" and "it."
Angry Guard Dog: Played with. While they are dogs who are guards, none of them are very angry. Doggo is the closest one there is to being angry most of the time.
Animated Armor: Or maybe a Mini-Mecha. The big, hulking Greater Dog is actually a normal-sized dog riding a massive suit of armor.
Battle Couple: Dogamy and Dogaressa are married, occasionally kissing each other in battle. Several of their attacks involve twin components that they control separately, such as axes that bounce towards each other or a pair of dogs that bark out rings of heart-shaped bullets.
Beware of Vicious Dog: For the most part subverted. While several guard dogs do in fact attack you on sight, and humorously worded signs warn about a few of these encounters, not all of these dogs are particularly ill-tempered, the ones who are only really act this way around unfamiliar humans, and in every case you can literally Pet the Dog and befriend it. The sign next to Lesser Dog's guard station parodies the classic warning: "aware of dog, pls pet dog."
Big Friendly Dog: Greater Dog looks gigantic and intimidating, but all it wants is some TLC, and will gladly leave you alone when it gets some.
Boss in Mook Clothing: The Dogi have a unique intro, difficult attacks, and are fairly difficult to spare. In addition, Dogaressa’s attacks become much harder if you kill Dogamy before her.
Boss Remix: The song that plays during Greater Dog's fight is a slowed-down version of "Dogsong", the regular fight theme re-orchestrated using dog barks from the Mario Paint soundfont.
Brother–Sister Incest: Parodied. In the Playable Epilogue, the Snowdin Canine Unit meets Endogeny, an Amalgamate of their relatives. Dogamy realizes that since his and Dogaressa’s parents are now the same being, he’s technically married to his sister. But then again…
Dogamy: Wait, we’re dogs. That stuff's normal.
Brother–Sister Team: In the Playable Epilogue, the Dogi realize that since their parents have merged together into one entity, they're now technically siblings.
Canis Major: Greater Dog, and to make the reference to the stars complete, Lesser Dog. Subverted when it turns out it's just a sort-of big dog riding around in a disproportionately large suit of armor.
Critical Hit: Parodied when you pet Lesser Dog enough to spare it, at which point the game text informs you that it's a "critical pet!"
Dark Is Not Evil: Dogamy and Dogaressa wear black hooded cloaks and wield battle-axes, but they're just as friendly as the other monsters when spared. Bonus points for being a sickeningly sweet-hearted couple.
Department of Redundancy Department: Lesser Dog has six Act options; "Check", "Pet", "Pet", "Pet", "Pet", and "Pet". Hmm, how could it possibly be Spared...?
Dogs Are Dumb: Varies. Lesser Dog and Greater Dog have mental capabilities only slightly higher than a non-anthropomorphic dog (although the latter is a non-anthro dog). Doggo is smarter, but his inability to see unmoving things hampers him, and he thinks the former two dogs are much smarter than they actually are. The Dogi seem to be the smartest overall, but even they aren't too complicated, allowing you to fool them into thinking that you're some kind of puppy if you roll around in the snow.
Dual Boss: Dogamy and Dogaressa, reflected by their attacks having two parts. Depending on which one you kill first (if you decide to kill them), the other will change their attacks based on their reaction to the other's death. Dogaressa flies into a rage; Dogamy just mourns…
Evil-Detecting Dog:
- The Dogi have great noses when it comes to smelling for potential human intruders, which is why they attack you in the first place. Fortunately, wallowing in the dirt will get rid of the human scent and help when Sparing them.
- Doggo can't see things that are standing still, with one exception; he will feel something very wrong and become afraid when the player approaches him on a No Mercy run. This is the first true sign of how the player's Killing Intent works.
Face of a Thug: Doggo looks like a typical gangster with wacky clothing and knives as his signature weapon. He's just as friendly as the other dog-type monsters. It's been speculated that he only dresses up like that because his reverse motion blindness (can only see moving things) makes him unaware of what he's wearing.
Foreshadowing:
- When in battle, the Dogi may reveal that they were runner-ups in a nose-nuzzling championship. You later learn who came first: Asgore and Toriel.
- If you keep ringing the bell on Doggo's sentry post after you’ve completed his encounter, he will hint at the other members of the Canine Unit.
Fun T-Shirt: The Dogi have each other's faces on their robes, unseen on their overworld sprites and only noticeable if you SPARE them or kill one of them, as their axes cover the other's chest in their battle sprites.
G-Rated Drug: Doggo likes to smoke dog treats. Likely the reason why the ESRB rating mentions "Tobacco References".
Gameplay and Story Integration: Doggo's inability to notice stuff that isn't moving is reflected in his blue attacks, which cannot harm a stationary player. If the player does get hit by them, they get noticed and he uses regular white attacks.
Gentle Giant: The Greater Dog is described as such when spoken about in Grillby's, and if played with and petted is more than content to lie down in the Child's lap… while wearing its hulking suit of armor.
Go Fetch: Use the Stick on any of them, and they'll run after it, allowing them to be Spared instantly.
Gratuitous Japanese: When you pet Doggo, the word WAN floats around him as he freaks out. 'Wan' is the Japanese onomatopoeia for a dog's barking.
The Guards Must Be Crazy: While none of them are weak, they seem to have a hard time actually guarding anything, thanks to their dog instincts. Papyrus comments on it while talking about Lesser Dog in one phone call.
Papyrus: This dog loves to be pet. That's its defining personality trait. Wait, why are they a Royal Guard and not me!?
Happily Married: The Dogi. One of the battle comments is that they are "saying sickeningly sweet things to each other".
Heroic BSoD: Killing Dogaressa will cause Dogamy to become depressed, and his attacks become completely impotent. On the flipside, Dogaressa slips into an Unstoppable Rage and gets even more powerful if Dogamy dies.
Keet: Lesser Dog gets excited when you pet it. Really, really excited. Pet it enough and it will go nuts when building snow dogs outside its sentry station, resulting in several sculptures of dogs with overly long necks.
Kill One, Others Get Stronger: Zigzagged for Dogi and Dogaressa during a non-Pacifist route. If Dogi dies first, Dogaressa goes on a Roaring Rampage of Revenge against you, complete with the faster moving axe attack, but if Dogaressa dies first, Dogi goes into a Heroic BSoD and all he can manage is a small dog feebly barking out a heart, alongside his defence dropping by 30, making him way easier to kill.
Leaning on the Fourth Wall: Doggo can't see things that aren't moving. If you try to talk to him, he gets jumpy and asks "Who's there?!" He can't see who's talking to him… because you can't move during dialogue.
Leitmotif:
- The Greater Dog has "Dogsong" playing during its encounter.
- "Dogbass" plays as the Dogi investigate the area, just before they attack.
Living Motion Detector: Doggo can only see things that are moving, a point very much stressed in the early-game to teach you about blue attacks.
Long Neck: Most of the humor value of a pacifist Lesser Dog encounter. The more you pet it, the more its neck telescopes out. With enough patience, its head can even go out of the top of the game screen, back down, and through the bottom.
The Lost Lenore: If Dogaressa dies first, Dogi is just left to mourn his dead wife.
Mini-Boss: All of them sans Lesser Dog are unique and are required encounters. Only the Dogi and Greater Dog take much effort to Spare or Fight, however.
More Deadly Than the Male: When fighting the Dogi, if you kill Dogaressa first, then Dogamy loses almost all will to fight and becomes a pushover. However, if you kill him first, Dogaressa becomes much more dangerous and harder to beat.
My Friends... and Zoidberg: Lesser Dog seems to be the Zoidberg of the Dog group. None of the other dogs mention it, and it appears as a random encounter enemy rather than a mini-boss encounter. It's also the only dog not to meet Endogeny; at the end of the game, it's still inside playing poker against itself. The NPC near Lesser Dog's station can also comment that Lesser Dog always ends up playing poker alone because it doesn't know how to express itself with the other dogs.
My Instincts Are Showing: Despite all of them being at least intelligent enough to wear clothes, they all love being petted and chasing sticks.
The Nose Knows: The Dogi depend almost entirely on their sense of smell to identify intruders. A crucial part of sparing them involves rolling around to disguise your scent.
No Smoking: Played for Laughs (considering smoking occurs elsewhere in the game), Doggo has a fondness for smoking dog treats, of all things.
Not So Stoic: Doggo seems pretty serious when you first meet him… and then you pet him, and anything that made him imposing vanishes.
Oh, Crap!: Doggo has this reaction when he's pet by something he's inferred to not exist. (Or at least not see.)
Overly Long Gag: Lesser Dog's neck-stretching gag can go on for a very long time and yield unique lines long after you can Spare it. It will also keep cropping up during the game afterwards.
Punch-Clock Villains: Once the player reaches Snowdin, they can all be found hanging out at Grillby's, and don't seem to care at all that you're there.
Punny Name:
- "Dogaressa" is the female form of "doge". "Italian ruler" doge, mind you, not that doge.
- "Dogamy" is a pun on the suffix "-gamy" being used for different types of marriage (monogamy, polygamy, etc.), as Dogamy and Dogaressa are married.
- A subtler one in Doggo's case — "doggo" is somewhat archaic slang meaning "to remain motionless and quiet to escape detection" (i.e., exactly what you need to do when facing Doggo).
- In a very downplayed example, Lesser Dog's 'dogger' is made of 'pomer-granite'.
Quirky Miniboss Squad: The royal guard all have weird quirks. Doggo's vision problems, Greater Dog's tendency to act like a regular dog, Dogamy and Dogaressa being Sickeningly Sweethearts, and Lesser Dog's increasingly long neck.
Real Men Wear Pink: Doggo, the most threatening of the dogs in appearance, wears a pink shirt with a dog face on it.
Roaring Rampage of Revenge: If Dogamy is killed before Dogaressa, Dogaressa flips out and becomes much more relentless in her attacks.
Rummage Sale Reject: In contrast with his squadmates (who wear armor or cloaks), Doggo wears a ridiculous outfit of a pink sleeveless shirt with a dog face on it and leopard-print pants. This may be a result of his inability to see still objects.
Saying Sound Effects Out Loud: Unsound Effects, rather. Lesser Dog's speech, if one can call it that, consists of sounds spoken out loud, like "pant pant" or "excited noises." As you keep petting it, it starts making sounds that no dog can or should make, including "plane takeoff" and "kettle whistling".
Screw This, I'm Outta Here: If you ignore Greater Dog for several turns, it will leave out of boredom.
Shields Are Useless: Despite carrying around a shield the size of itself, Lesser Dog has the lowest Defense out of all of them.
Sickeningly Sweethearts: The Dogi are said to call each other overly cute names during battle.
Spell My Name with a "The": In-battle text refers to the female of the Dogi as "the Dogaressa".
Stealth Pun: They're guard dogs.
- One of Greater Dog's attacks is a tiny sleeping dog. If you move at all, you'll wake the dog and cause it to attack. Let sleeping dogs lie.
Stellar Name: Lesser Dog and Greater Dog's names derive from the English translation for the names of the dog constellations, Canis Minor and Canis Major.
Tertiary Sexual Characteristics: Dogamy has Big Ol' Eyebrows and a pseudo-mustache, while Dogaressa has long eyelashes. They're nearly identical otherwise.
Theme Naming: All of them have "Dog" in their names. This carries over to Endogeny late in the game.
Tiny-Headed Behemoth: Greater Dog initially seems to be this. It's actually a normal-sized dog wearing a giant suit of armor.
Top-Heavy Guy: Greater Dog, whose chest and arms are gigantic compared to its positively tiny head and legs. Except that it's actually just a regular-sized dog in some sort of pilotable armor.
Truth in Television: Doggo's inability to perceive static objects is a real-life disorder.
Unique Enemy: Lesser Dog, unlike the other dogs, is fought in a random encounter on one screen. It's otherwise still a mini-boss, albeit one of the simplest ones.
Vocal Dissonance: The Greater Dog has a very deep bark, which is fitting for the kind of person who would normally wear armor as big as it does, but not for the average-sized dog it actually is. Unusually, this goes both ways, in that Greater Dog introduces itself from its snow poff by sticking its head and tail out, then giving a couple of high-pitched, yappy barks, which makes it seem cute… until it reveals that it somehow hid its entire massive body underneath the snow. This makes it seem like a squeaky-voiced titan instead.
Warm-Up Boss: All of them teach you a different mechanic that's important to know going forward. Doggo teaches you about Light Blue attacks that don't hurt you if you stand still: if you didn't encounter a Vegetoid in the Ruins, this is the first non-white bullet you'll see. The Dogi teach you that certain ACT commands change in response to other ACT commands and thus you'll have to do this sequentially to get to them to back down. Lesser Dog's use as a tutorial is questionable, since it stops fighting after the first pet, but repeatedly petting it shows that repetition can have different effects. And Greater Dog combines all of these, using Light Blue bullets, having ACT commands that change in response to previous ACT commands, and requiring the same ACT to be used multiple times to spare it.
Weaksauce Weakness: Petting plays a significant role in scoring a Pacifist victory against all of them. They're also all vulnerable to a thrown stick. Doggo, in particular, can't hurt you if you hold still.
Weapons-Grade Vocabulary: One of the Greater Dog's attacks is a tiny sleeping dog that, if woken up by moving, will send damaging "BARK"s at your SOUL.
What Kind of Lame Power Is Heart, Anyway?: Doggo is really good at sensing motion. And that's literally the only thing he can see, so anyone standing perfectly still is completely invisible to him (and this is reflected in his attacks, which are all of the blue variety and can be avoided by standing still).

Mad Dummy

Mad Dummy/Mad Mew Mew

"Futile.
Futile!
FUTILE!"

^{Click here to see the Nintendo Swich version's form.}

A haunted dummy that hates boring people and who desperately wishes to be corporeal.

Aborted Declaration of Love: In the fight with Mad Mew Mew, she reveals that she loves Undyne, but Undyne already loves Alphys and she doesn't want to interfere with that.
Adapted Out: An inversion. Their Mad Mew Mew form is exclusive to the Nintendo Switch and Xbox versions, and isn't present in the PC or PlayStation versions.
Ambiguous Gender: A non-corporeal ghost (that was never a living person), only ever referred to as "them". Until becoming Mad Mew Mew, who is referred to as a girl.
Anger Is Not Enough: The Mad Dummy cannot defeat you with anger. At most, they can keep you trapped forever (or at least they would have had Napstablook not intervened).
Attack Backfire: The Mad Dummy is defeated by the Player Character homing their attacks on themself.
Be Careful What You Wish For: Wants to unite with their vessel and become a corporeal being. In a Genocide run, they succeed… but unfortunately, this also means they can be attacked and killed.
Become a Real Boy: Wants to truly unite with their physical vessel, rather than merely possessing it. In the Pacifist route, becoming a real girl is still her goal. This time, however, she's trying to become one with a life-sized Mew Mew Kissy Cutie doll, and realizes that she can't do so through extreme anger.
Belly Mouth: Instead of a stitched seam, they have a jaw of teeth below their midsection. Averted as Mad Mew Mew, since the doll has an actual mouth, though the dialogue box occasionally says a tinny, pre-recorded voice is coming out of a speaker in Mew Mew's chest, likely as a feature of the toy.
Brick Joke: Beating her unlocks an anime-themed border for the game, which is called the "Real" or "Not Real" theme depending on whether you told Undyne if anime is real or not.
Cat Girl: As Mad Mew Mew. And even though they are just a ghost possessing an oversized toy, it still counts.
Cats Are Mean: They still retain their aggressive and cutthroat personality even after taking over the body of the feline doll.
Clingy Jealous Girl: Subverted. After learning that Undyne and Alphys have already hooked up, she looks like she's going to go down this route, but instead decides that she will respect their relationship and is glad that Undyne is happy. She does appear to harbor slight jealousy towards Alphys in the alarm clock dialogue, though.
Mad Mew Mew: Well, if she's got somebody else... THEN YOU KNOW WHAT I'M GONNA DO TO THEM!?? I'LL RESPECT THEM!!! I'LL RESPECT THEIR RELATIONSHIP!!! HAHAHA!!! HAPPY FOR HER!! NOTHING BUT THE BEST!!! BEST OF LUCK!!!
Colour-Coded for Your Convenience: The battle in the Switch version gives three different colored orbs to avoid, based on the colors of the Nintendo Switch's Joy-Con controllers. Red and blue orbs can be dodged only by the corresponding-colored half of the player's SOUL, while white orbs have to be dodged altogether.
Combat Sadomasochist: As Mad Mew Mew, she makes it clear that — as Undyne's training dummy — she harbors a crush on Undyne and relishes the thought of getting stuck full of spears.
Comically Missing the Point: Mad Dummy "rescued" the Mew Mew Kissy Cutie doll from "a science-y place" after assuming that whoever owned it performed nasty experiments on it, apparently unaware of Alphys's Otaku nature.
Chekhov's Gunman: They're the cousin of the Training Dummy in the Ruins, and their reason for attacking you relates to how you handled the fight with them.
Dark Magical Girl: After possessing the Mew Mew doll, they gain all types of new magical abilities because their new body is essentially the replica of a genuine Magical Girl. However, they still retain their anxiety and rage of not being able to successfully gain a body of their own.
Despair Event Horizon: If the player survives long enough in the battle against Mad Mew Mew, she'll sadly wonder what she's doing wrong, since she can't seem to fuse with anything. It's only then that the player can talk to them and calm them down.
Deadly Dodging: You can only hurt them with their own bullets, which come from other dummies that they summon.
Death by Irony: They spend the whole fight trying to kill you out of revenge for how you treated their cousin, sort of. In the No Mercy route, they're so furious at your terrible personality that the raw anger causes their spirit to bond with the dummy, making them corporeal and perfectly killable for the first time.
Death Glare: Implied by one message in between turns:
Dialogue Box: Mad Dummy glares into a mirror, then turns to you with the same expression.
Disproportionate Retribution: Their reason for trying to attack you if you wasted time until the Training Dummy flew away? You're really boring, and boring people don't deserve to live.
Distaff Counterpart: Mad Mew Mew is one to Mettaton EX, a ghost possessing a robotic body and had previously taken on a less anthropomorphic form.
Easily Forgiven: Upon becoming corporeal, the Dummy will be so overjoyed that they instantly let you go despite you being a mass murderer.
Everyone Has Standards: Despite Mad Dummy being a self-absorbed Jerkass, as Mad Mew Mew, she draws the line at interfering with Undyne and Alphys' relationship out of jealousy, instead vowing to respect their love and only wishes the best for Undyne.
Evil Laugh: When they realize that you can't harm them and they can't beat you, they laugh at the prospect of keeping you stuck in battle forever.
Foreshadowing: They try to do the same thing that Sans does at the very end of the Genocide route: make their turn last forever so you can't have yours.
Gender Bender: Downplayed, as they go from using They/Them pronouns when possessing a simple training dummy to using She/Her upon possessing the female Mew Mew doll.
Ghostly Goals: To fuse with their current vessel so they can achieve a form along with using your SOUL to leave the Underground and try to find work as a shop window dummy. The battle with her as Mad Mew Mew also reveals that she wants to become Undyne's training dummy again, just in a much cuter form. If spared, she makes additional plans to go into public performances and rival Mettaton.
Hair-Trigger Temper: No matter how you dealt with the Training Dummy, they will get angry regardless of your action. There's a pretty good reason why they're called the Mad Dummy.
Headless Horseman: She jokes about becoming the world's cutest dullahan should you knock off her head for a third time. But she states she would only do so if she had a giant cat as a steed.
Hidden Eyes: Briefly gets these as Mad Mew Mew when she realizes that Undyne is already in a relationship. She quickly gets over it, though. She also has these when she starts to realize that all her anger and fighting isn't helping her fuse with her new body, leading the player to tell her that there are other feelings that might help her fuse, such as LOVE (actual love, not Level Of ViolencE).
Hope Spot: In the Genocide route, they get so angry they end up fusing with the dummy itself to become fully corporeal, AKA their 'lifelong dream'. Unfortunately. this leaves them open to being killed by the player, and if you want to continue the Genocide route, you have to kill them. Sparing them will end up averting the route.
In Spite of a Nail: Despite Mad Mew Mew's fight and subsequent possession of the Mew Mew doll only occuring on the Switch version, it's treated as canon in the Xbox version, where she'll show up in Sans' casino already possessing the doll, and the alarm clock dialogue taking place after True Pacifist has Mettaton confirm that she's possessed the doll.
Interface Screw: Mad Mew Mew's battle features a completely unique, "half-red/half-blue" SOUL mode. It restricts your movement to three or five spaces on a grid, but also allows you to control each half of the SOUL individually with each analog stick, which is necessary to avoid most of her attacks.
It's All About Me: Their goal in trying to kill you? Leave the underground and get work as a dummy in a department-store window. (They also say they're trying to avenge their cousin, but can't even remember their name.) Even Mettaton is trying to save humanity while becoming a star.
Jerkass: They pretend they're attacking you to avenge their cousin, but that's just an excuse. Really, they just want the player character's soul for their own selfish ends. They never show remorse for it, either. Even on Genocide, they're immediately okay with you and let you go once they get what they wanted, and their supposed rage at your murderous actions disappears completely.
Jerkass Realization:
- In the True Pacifist ending, they're grateful that the monsters are free and finally admit they acted like a dummy.
- As Mad Mew Mew, she realizes that all her extreme anger isn't helping her fuse with the life-size Mew Mew Kissy Cutie doll she's inhabiting, and starts to try out other feelings, such as LOVE, which is more profound if the player shows their LOVE by sparing her.
Karma Houdini: By far the most hostile and selfish monster you face — even Undyne, as aggressive as she is, at least has the excuse of acting for the good of her people, and Flowey, despite being the main villain, has a legitimate reason for what he does. But by virtue of being a ghost, it's also one of the only monsters you can't kill no matter what unless you're on the No Mercy run. Thankfully, the True Pacifist ending and the battle against Mad Mew Mew give them a bit more character depth.
Large Ham: Between their furious yelling and Verbal Tic, Mad Dummy is definitely one of the more over-the-top monsters in the Underground.
Laughing Mad: Naturally. They truly break into this after their last attack, cackling loudly to the point that their separate pieces start to fly apart out of a combination of anger and borderline craziness.
Leaning on the Fourth Wall: In the Switch version, she uses a new SOUL mode based on the Nintendo Switch Joy-Con.
Leitmotif: "Dummy!", a remix of "Ghost Fight". Her theme as Mad Mew Mew is also a remix of the same song.
Losing Your Head: If attacked, they'll smash into pieces (head included), and then just reform back together since they haven't actually fused with the training dummy yet. Attacking her as Mew Mew causes her head to fly off. However, because she's still Nigh-Invulnerable as a ghost, the attack doesn't do any damage, and she just puts her head right back on.
Mathematician's Answer: The 1.001 update changes their CHECK description so that, instead of a numerical value, their defense is simply listed as "YES".
Mean Boss: To say that they're upset at their mini-dummies for accidentally shooting them is putting it lightly. They fire all of them mid-battle because they're sick of getting shot by them.
Mecha-Mooks: They will eventually dismiss the regular bullet dummies for hitting them instead of you, causing them to replace them with robotic dummies that fire homing projectiles instead (they're not much better, though).
Mini-Boss: Has more pomp and circumstance than a regular enemy, but doesn't affect the overall plot.
Mirror Character: In her appearance in the alarm clock dialogue, she's pinned as one to Mettaton; they're both Napstablook's cousins and they accidentally cause them to leave the party after getting into a fight for no reason. They also are silently jealous of Undyne and Alphys, Undyne for Mettaton and Alphys for Mew Mew, for taking away their only other friend besides Blooky. They've also both become corporeal by possessing and fusing with mechanical bodies made by Alphys.
Misguided Missile: In their second phase, the missiles their dummies fire must be redirected so they can hit the Mad Dummy. These missiles stop tracking you after a few seconds and continue flying off; this is required to hit them because the missiles usually don't leave the range of your SOUL's movement.
Musical Spoiler: If her name didn't tip you off, Mad Mew Mew's boss theme is another remix of Ghost Fight with the more aggressive and repetitive tones of Dummy!, giving away that she's Mad Dummy.
Nigh-Invulnerability: Being a ghost possessing a dummy, they are immune to physical attacks (both as Mad Dummy and as Mad Mew Mew). Subverted in a No Mercy run, where they manage to become one with the dummy through sheer anger, thus making them corporeal enough to hit. Also subverted with Mew Mew once she asks the human to show her what LOVE is... and they can respond by destroying the doll. Then she reveals she's still "alive" and that the doll's destruction didn't affect her.
No-Sell: If you hit them with your own attack, they'll just rebuild themself, no worse for wear.
Optional Boss: Reappears in the Switch version as Mad Mew Mew, having stolen and possessed Alphys's life-sized Mew Mew Kissy Cutie figure.
The Power of Hate: The dummy believes they can Become a Real Boy if they become angry enough. This only works in a Genocide run, as every other time, the Dummy can't get angry enough to fuse with their vessel. She continues with a different body afterwards that she finds perfect, but she realizes that The Power of Love would be a better way of going about fusing with the doll.
Psycho Knife Nut: Parodied. Once they get tired of getting Hoist by His Own Petard, they will try to throw knives at you. They only have one, though.
Mad Dummy: I DON'T NEED FRIENDS!!! I'VE GOT KNIVES!!!
Mad Dummy: I'M… Out of knives.
Psycho Pink: The Mad Mew Mew doll already had a pink coloration, and by fusing with it, they still retain their psychotic persona.
Puzzle Boss: They're immune to physical attacks (since they're a ghost) and refuse to back down and let you spare them. The only way to progress is to trick them into using their own magic projectiles against them.
Replacement Mooks: When their first mooks keep failing in their attempts to hit the human SOUL, Mad Dummy replaces them with an upgraded version that shoot homing projectiles.
Rule of Three: They tend to repeat their words three times before they make any progress. This even drips into their song (a remix of Napstablook's theme) which constantly repeats chords three times before continuing on with the song. This is also how many times you need to ticklish the Mew Mew Doll before she reveals her true identity, and her new battle theme Spider Dance also tends do repeat some segments thrice before continuing.
Screw This, I'm Outta Here:
- Finally decides they've had enough when Napstablook cries their magic tears on them.
- In a No Mercy run, the Glad Dummy will make the same kind of exit as the standard Dummy if you fool around too much. This is one of the less obvious ways to cancel a No Mercy run without resetting.
Second Law of Gender-Bending: Mad Dummy is effectively genderless and only ever referred to as "they/them". Upon gaining the Mad Mew Mew form, however, she immediately embraces female pronouns, and gushes about how she feels that this new identity and body is much more in tune with her true self.
Shout-Out:
- They're one of the few truly ruthless monsters you meet in the Underground: they're immortal, they throw knives as a desperation attack, and they frequently shout one word or phrase three times in a row that either directly means or is a synonym of "useless". MUDA MUDA MUDAAA! The reference is made more obvious with Mew Mew sporting a KONO DIO DA!-like expression◊.
- None of your attacks can hurt them, but the only thing that can is a rain of Napstablook's tears, which might be a reference to how Ghost-type attacks are super effective against other Ghost-types in Pokémon.
- Her appearance as Mad Mew Mew resembles Ichigo, the lead character of Tokyo Mew Mew, tying in with Mew Mew Kissy Cutie being a riff on that series.
Suddenly Shouting: Their speech pattern goes normally voiced, louder, and finally IN ALL CAPS.
Surrounded by Idiots: Their mini-dummies that shoot magic attacks. After they take too many of them, they get angry(er) and fire them in a huff.
Tactical Suicide Boss: Their attacks are the only reason they can be hurt. To their credit, they realize this and change up their attacks twice in an attempt to avert it. However, all of their good attacks are the ones they can be hurt by; the one that can't hurt them (the knife) only has one shot, and the battle ends after they throw the knife.
Training Dummy: The Mad Dummy's vessel is Undyne's training dummy, which makes them virtually indestructible. The Switch version has them abandon it in favour of the Mad Mew Mew form.
Trans Tribulations: While Mad Dummy becomes euphoric upon transforming into Mad Mew Mew (changing her pronouns from "they/them" to "she/her" in the process), describing it as her ideal self and claiming she can live a more fulfilling life, she also becomes upset when she thinks she can't totally fuse with her new body, despondently asking if something's wrong with her.
Took a Level in Badass: Mad Dummy is almost completely dependent on unreliable minions to do their fighting for them, possessing only a single slow, inaccurate, knife to fight with on their own. As Mad Mew Mew, she's picked up very dangerous new powers, barraging the player's SOUL from multiple directions with projectiles that leave very little wiggle room.
Verbal Tic: Repeating themself three times, each getting progressively louder, is their Verbal Tic. Even referenced in their battle theme where certain lines play three times before carrying on with the rest of the song.
Victory by Endurance: The only way to win in the battles with them, including the Switch version, is to survive long enough. In the Mad Dummy battle, Napstablook's tears drive the Dummy away. As Mew Mew, she hits a Despair Event Horizon after her second attempt at fusion fails, allowing the player to talk to her.
We Will Meet Again: If the player "kills" her as Mad Mew Mew, she'll vow revenge against the human in the future before her broken, busted body flies offscreen. Somehow.
Wins by Doing Absolutely Nothing: At the end of the fight, they try to do this to you. Since you can't hurt them (directly) and they can't hurt you (anymore), they decide that the only way to keep fighting you is to refuse to end their turn, keeping you trapped "forever". It fails miserably when Napstablook starts damaging them with their tears.

Royal Guards

RG 01 & RG 02

"Like, team attack!"

"... team attack."

Guards. Royal ones.

24-Hour Armor: Except for when 02 takes off his breastplate because of the heat, they are never seen without their armor.
Affably Evil: At least RG 01 is this. Immediately after the guards' Double Take, he politely tells the player that they'll have to kill the player. They also look rather disinterested during their fight.
Armored Dragons: RG 02 is a dragon, according to Undyne. Justified, as he is still a monster, and as such, he is vulnerable to LOVE.
Big Damn Heroes: If you spare them, they both become this to the Nice Cream Guy as they buy out his entire stock, persuading him to stay in business.
Black Knight: In appearance thanks to their glossy dark armor, large swords, and face-concealing helmets. Ultimately, however, 01 is a loud frat boy and 02 is his shy wallflower friend.
Despair Event Horizon: In contrast with 02, if only 01 is left alive, his reaction basically goes from swearing vengeance, to anguish, to despair.
Everyone Calls Him "Barkeep": They're only referred to as "01" and "02," even when speaking to each other.
Fratbro: 01's characterization, being mostly this with a dash of Surfer Dude thanks to his constant use of the words 'like' and 'bro.'
Funny Animal: It's pretty hard to tell at first glance, especially since they're wearing all-encompassing armor, but 01 has rabbit ears and 02 has draconic fins on the sides of his head and his chest is covered in scales. If you call Undyne standing in the area where you fight them, she confirms them as a rabbit and a dragon.
Getting Hot in Here: The Royal Guards are located in Hotland, and use cooling dirt to keep their suits of armor cool. Washing it off causes one of them to get overheated, so he takes it off. It also gets the other guard overheated and too distracted to fight, but in a different way.
The Guards Must Be Crazy: Literally. When you first meet them in Hotland, both warn you about a dangerous human Undyne warned them about and put a kill-on-sight order on them, and the reason why they try to catch you the second time on a neutral run? They're evacuating the area and try to bring you to safety. RG 02 picks up on this, however.
"Just Joking" Justification: When 01 confesses his love to 02, and it momentarily looks like that the latter doesn't reciprocate, the former backpedals and claims it was a joke. 02 does reciprocate, however.
Kill One, Others Get Stronger: If one of the guards are killed, the other's attack becomes a lot more harder to dodge and become much more intense in nature.
Like Is, Like, a Comma: 01 has a habit of saying "like" when it isn't necessary.
Manly Gay: If 01's interactions with 02 say anything. Humorously, Undyne of all people seems to be completely oblivious to it if you call her in the area they're fought, referring to their "platonic friendship."
Mini-Boss: You need to fight them to move forward and their battle is unique, but they're secondary characters and beating them isn't particularly hard.
The Quiet One: 02, who just mumbles things and sighs where 01 is shouty and enthusiastic.
Red Oni, Blue Oni: 01 is red, 02 is blue.
Roaring Rampage of Revenge: Killing one of them results in the other's attacks becoming much more fierce, though 02 seems more angry in the flavor text and 01 just seems to be in despair.
Shirtless Scene: 02 gets very hot and sweaty during your fight and decides to take off the top of his armor. This makes 01 very nervous.
Shout-Out: Their Genocide route CHECK description is a direct quote from Banana Yoshimoto's 1988 novel, Kitchen:
I see two lovers staring over the edge of the cauldron of hell.
Do they both wish for death? That means their love will end in hell.
I couldn't stop laughing.
Those Two Guys: Mostly interchangeable? Check. Completely inseparable? Check.
Together in Death: If they are killed. Checking them in No Mercy nets this dialogue: "I see two lovers staring over the edge of the cauldron of hell. Do they both wish for death? That means their love will end in hell. I couldn't stop laughing."
Tranquil Fury: If you kill 01, 02 is implied to have this, as he doesn't say much but the flavor text paints him as furious at you.
Video Game Cruelty Potential: You can kill them after you get them to admit their feelings for each other.
What the Hell, Hero?: Killing 02 when they can be spared gets 01 to ask you why you had to do that.
You Are Number 6: Their names really are 01 and 02.

So Sorry

"Ahhhh!!! I'm late!!! I'm late!!! I'm so sorry!!!"

This creature is definitely in the wrong time and space!

Apologetic Attacker: He's not even trying to attack you; his "attacks" are just being generally clumsy in his attempts to draw you a picture, with a tail strike or tossing paper around. As if his name wasn't a more obvious indication.
Apologises a Lot: It's in his name!
Art Initiates Life: He's an artist with a magic pencil, but accidentally draws some monsters that come to life in an attempt to draw a picture of you.
Author Avatar: Of one of the Kickstarter backers.
Blind Shoulder Toss: One of So Sorry's attacks is to turn his back to the player and toss crumpled-up paper behind him.
Breaking the Fourth Wall: Reduce his health to a certain amount and he'll try to persuade you not to kill him because he doesn't even give out enough EXP to level you up at level 1. He's right. He only gives one EXP.
The Cameo: One of several characters added to the game by a Kickstarter backer.
Fixed Damage Attack: Inverted. All your attacks do exactly 1/11 of his HP.
Flunky Boss: He'll accidentally summon a few crudely drawn monsters partway through the fight, though they can be sent away easily.
Guide Dang It!: Reaching So Sorry requires having your computer's time set to a very specific setting and going through the secret path that opens up in a specific place. It is very unlikely to have this happen by accident.
His Name Really Is "Barkeep": One of the first things he says when encountering the player is "I'm so sorry!" He is So Sorry.
Holiday Mode: Fighting him at all also requires a specific date and time.
Leitmotif: "Wrong Enemy !?"
Motor Mouth: Noticeably during the fight, his text prints much faster than any other character in the game.
Only Known By His Nickname: He does have a real name^*Samael D. Butterdragon, being a preexisting character, but that information isn't anywhere in the game. This might be to avoid family-unfriendly Google associations.
Optional Boss: So Sorry (yes, that's his name) is very obscure to find. There's a hidden path in Hotland near Sans's hot dog stand. The encounter still doesn't trigger unless all of the elevator stops are available and the internal clock is set to October 10, 8:00pm.
Shy Finger-Twiddling: Constantly twiddles his index fingers together in battle.

Muffet

"Don't look so blue, my deary~"

A spider girl who's having a bake sale. If she invites you to her parlor, excuse yourself.

All Webbed Up: Her special soul effect, which turns your soul purple. You're confined to hopping between horizontal tracks rather than floating freely like normal.
Anthropomorphic Food: Has a "pet" muffin monster that attempts to eat the player's SOUL, chasing them upwards in a Rise to the Challenge scenario.
Arachnid Appearance and Attire: Muffet has a five-eyed, spider-like face and a total of 8 limbs. Most of her attacks involve spiders.
Bad Boss: Downplayed; making her spider friends into pastries is one thing, but feeding them to her pet cupcake monster while trying to attack you is another. The spiders don't mind, though.
Battle Boomerang: One of her projectiles acts like this, with it flying almost entirely across one of the lines before flying backwards. Going with the food theme, they're actually croissants.
Blue-and-Orange Morality: Even if you're in the No Mercy route and she's perfectly aware that you're a violent psychopath, she's perfectly willing to let you go when she finds out that you've never harmed any spiders. There's also the fact that she has it out for you in any route because she thinks you hate spiders, but bakes spiders into her own pastries.
Boss-Altering Consequence: Gameplay-wise, she can be defeated in the first turn if you eat a spider-based food item in front of her, thus proving that you care about her cause! Buying directly from her beforehand (at a ridiculously inflated price) will outright skip the battle.
Bribing Your Way to Victory: You can pay Muffet some of your money to have her reduce her attack power on any turn. This price goes up every time the option is taken. Alternatively, you can avoid fighting her by buying food from her, or by eating something you bought from an earlier spider bake sale.
Calling Your Attacks: After each turn, a small, normal spider will walk on screen holding a sign with pictures of donuts, croissants, spiders or a cupcake, indicating what type of attack Muffet will use next.
Carnivore Confusion: The reason she attacks is that she was informed that you hate spiders and killed a lot of them, yet she herself cooks other spiders into her pastries and cider. It may have something to do with monsters being made of magic, but it's still very strange. Then again, real-life spiders sometimes do eat each other. It could also be that, as a predator, she views killing something for food to be perfectly acceptable, but killing something for fun to be cruel.
Color Motif: Purple.
Cute Little Fangs: Muffet sports a pair that always protrude from her mouth.
Cute Monster Girl: You have to admit, she does look adorable in her little outfit and matching tea sets.
Edible Ammunition: In addition to sending spiders out, she'll toss in donuts and croissants when attacking. Considering her own Carnivore Confusion, the spiders themselves also count as this.
Everyone Has Standards: Implied. It seems that, while she eats spiders and doesn't mind other people doing the same, she won't tolerate cruelty towards them, like killing them for other reasons or torturing them.
Extra Eyes: Unlike actual spiders, Muffet has five eyes instead of eight.
Fantastic Racism: Implied. The player can kill as many monsters as they want, and Muffet will agree to let them go alive when she learns that no spider has been injured. In addition, if the player bought and ate in front of her a product sold by the spiders in the Ruins, Muffet will immediately let them go, explaining that she does not want to hurt a spider's friend, implying that she respects the other monsters only on this condition.
Giant Spider: While not very beastly herself, she is still a spider that is as big as a human. However, her pet is far more monstrous in comparison and is very much larger than their master.
Giggling Villain: "Ufufu~"
Hartman Hips: She has quite a large "tuffet" in comparison to her limbs. Possibly just puffy pants, but then again spiders do have large abdomens.
Hired Guns: Was paid a substantial amount of money to attack the human, although it's not specified if her benefactor was Mettaton. The use of Ghost Fight’s leitmotif implies it may have been Mad Dummy, but this is never confirmed.
Hold the Line: In order to Spare her, you need to last long enough for a spider to come along with a telegram for her saying that you haven't hurt any spiders or that you supported the bake sale in the Ruins. You can skip right to the note by eating something you bought from the bake sale back in the Ruins.
Hypocrite: She attacks you because she believes you kill spiders. You know, those same spiders she makes her pastries out of? Of course, her anger towards you seems more directed at you being cruel to spiders and torturing them rather than simply killing them to eat them like she does.
I'm a Humanitarian: Spider cookies and spider cider, made by spiders, for spiders, of spiders! Muffet herself pours you a cup full of spiders during the boss fight with her. Of course, real-life spiders are often cannibalistic, so this is totally normal for them.
Interface Screw: She's the only mini-boss to use a SOUL Mode. She turns your SOUL purple, restricting your vertical movement; you'll have to jump between three horizontal strands of webbing to dodge her attacks.
Intrepid Merchant: Holding a bake sale in the middle of Hotland. Pastries made by spiders, for spiders, of spiders!
Leitmotif: "Spider Dance", which is partially a remix of "Ghost Fight".
Made from Real Girl Scouts: All of the products of her spider bake sale are made with real spiders. She also intends on using the protagonist as an ingredient.
The Man Behind the Woman: Not she herself, but a mysterious figure who tipped her off that you hate spiders and offered her a lot of money for your SOUL. The only clues as to the identity of this figure is that they had a "sweet smile" and that Muffet saw them "changing shape" in the shadows. It is later revealed that this was Mettaton, presumably using his as-of-then unrevealed (either to the public or the player) EX form to remain incognito before reverting to his usual box form.
Marathon Boss: Muffet's fight is significantly longer than most of the mini-bosses you've encountered up to that point, with only the Mad Dummy having a long boss fight. Be prepared for a lot of trouble if you don’t have any way of skipping her fight.
Meaningful Name: Her name is an obvious reference to the "Little Miss Muffet" poem, in which a spider frightens away a young child.
Mini-Boss: You must fight her in order to move forward, and her battle is rather unique and hard, but she has no impact on the narrative, and you can even skip the whole battle if you do the right thing.
Money Fetish: You can pay her money in battle to reduce her attack power, and the ways to skip fighting her both involve spending money. Also, she was hired by someone for a lot of money to take the player's SOUL. Although to be fair, she has a pretty good reason for wanting it.
Monstrous Cannibalism: Not only does she use other spiders as filling for her baking, she pouts that she should have webbed Alphys up and turned her into pastry filling. Considering that large spiders are known to eat smaller spiders (with females in particular often eating the exhausted males after mating), it's not too surprising, though it also makes her a hypocrite for attacking you because you supposedly harm spiders.
Multi-Armed and Dangerous: She has six arms and two legs for a total of eight limbs. Two of her hands are carrying teacups, while two others are carrying teapots. Of course, she’s a spider, so having eight limbs is no surprise.
Multi Armed Multi Tasking: She uses a pair of her arms to hold two teapots and another pair to grasp two teacups.
Nice Job Breaking It, Hero: Letting her ramble on a No Mercy Run reveals Alphys personally warned her about you during the evacuation, and left an escape path leading to the capital. Upon using said path, the Hotlands would seal up behind her and trap you outside. Unfortunately for Alphys, Muffet refused to abandon her nest and completely shrugs off the evacuation, preferring to kill you herself. As a result, you simply murder her and move on through the Hotlands unimpeded.
Perky Goth: As a spider, it is fitting that she would wear gothic attire, however, she is surprisingly upbeat albeit a bit mischievous.
Perpetual Smiler: Keeps it even when dying or having her soul sucked out.
Pet Monstrosity: A giant, cupcake-like spider monster that has an intense appetite? Perfect pet for someone like Muffet.
Pinball Projectile: If she angles her donut projectiles, they'll bounce off the walls of the dodge window.
Plot-Irrelevant Villain: Despite having her own theme and a unique gimmick, she's ultimately little more than a Miniboss who has nothing to do with the plot of Hotland or the game overall.
Psycho for Hire: She was offered a lot of money to take the protagonist's SOUL.
Purple Is Powerful: She is a purple humanoid spider who can turn your soul purple and force it to stick to her webs.
Rise to the Challenge: Her cupcake monster acts as this; it chases your SOUL upwards across several lines for quite a while. The wall is the easy part in this case; the hard part is the mass of spiders that are being sent down to the monster while you're trying to climb upwards.
Say It with Hearts: Tildes, actually~
Seductive Spider: She definitely fits the bill. She's a Cute Monster Girl Spider Perky Goth and her battle has more than a hint of being a seductive dance, what with her description being: "If she invites you to her parlor, excuse yourself." Plus, her battle theme is literally called Spider Dance.
Signature Laugh: Ahuhuhuhu~
Skewed Priorities: During a No Mercy run, she knows and acknowledges that you are a bloodthirsty mass-murderer. She's still perfectly willing to spare you, though, simply because despite all the people you've killed, you still never harmed any spiders among them.
Skippable Boss:
- If you buy an item from her bake sale — unlikely, since everything costs 9999 G — she won't fight you, unless you're on a No Mercy run. Alternatively, eating a Spider Donut or Spider Cider in-battle with her will cause her to spare you instantly, letting you end the battle as early as the first turn, before she has a chance to attack.
- She'll offer to spare you immediately on a No Mercy run because sure, you've killed a lot of monsters, but you haven't hurt any spiders.
Spiders Are Scary: At least, when you don't buy their baked goods. Subverted for the most part, as she's pleasant otherwise.
Spider Swarm: Most of her attacks involve swarms of spiders or swarms of pastries.
Spontaneous Choreography: Two text boxes that display at the beginning of your turn note that the spiders are clapping to the music, and that Muffet eventually joins them in a synchronized dance.
The Tease: She'll offer some rather suggestive lines if you opt to stay in her web after she decides to spare you, and tells you that you're free to come back and let her tie you up any time.
Too Dumb to Live: Let's see...refuses to evacuate from an Omnicidal Maniac during the No Mercy Route, calls them rotten to their face, attacks them even though she most likely heard the fates of those who did the same....
To Serve Man: She initially intends on using the protagonist as ingredients in her pastries, but grumps that they don't look very tasty.
Vague Age: Her creator described her as "a lil' baby spider monster", but clarified that it wasn't literal. She's seen running her own business and she addresses the protagonist as "deary".
Verbal Tic: Her sentences end with tildes, like this~
Well-Intentioned Extremist: She needs money for the purpose of raising funds to rescue the spiders trapped in the Ruins, as they cannot make it past Snowdin's cold weather.
Zero-Effort Boss: You can easily skip her battle by either eating the Spider Donut or Cider in front of her during the battle, or donating 9999G in her bake sale in Hotland, which doesn't initiate it at all.

Shopkeepers

Nice Cream Guy

"It's the frozen treat that warms your heart!"

A Nice Cream salesman who totes his cart to several places around the Underground as you travel. Business hasn't been booming, though…

Amazing Technicolor Population: He's a blue rabbit-like creature.
Break the Cutie: If you don't spare a mandatory encounter by killing the monsters involved, he will remain upset and hopeless about his business, since said encounter had the monsters buy all of his Nice Cream if they were spared.
Cannot Tell a Joke: According to Burgerpants, he thinks that the nice messages on his Nice Cream wrappers count as jokes.
The Ditz: He's not very good at thinking out his stand locations. The first is in an ice region, while the second is in a cave that's off the main path. The third location at least makes some sense, being in Hotland, but unfortunately he's put himself outside a fancy hotel that contains a fast food restaurant that sells name-brand frozen treats (MTT-brand Starfaits), past what would normally be the back entrance to the hotel (the main entrance being the side facing New Home), guaranteeing that the only people who would potentially visit would be people travelling to/from Snowdin or Waterfall (or who had business in Hotland proper), and didn't care about the MTT-brand products. Thankfully, sparing one of the major encounters means the third location actually works well for his business. Finally averted in the credits, as he does the most logical thing and starts selling Nice Cream at a beach.
Dungeon Shop: His first two locations are located in the middle of Snowdin and Waterfall. The one at Hotland is past the point enemies spawn, so it doesn't count.
Everyone Calls Him "Barkeep": The only character that mentions him in dialogue simply calls him "the Nice Cream guy".
Foil: A cheerful guy despite his business failures, in contrast with Burgerpants, who is successful but loathes his job.
Intrepid Merchant: He seems to be following the same trail as you, though this means that he sets up shop in the worst places possible.
Nice Guy: He's always cheerful with his customers, and puts all sorts of compliments in the wrappers of his icecream.
No Name Given: Never gives out his name, and nobody else mentions it. In Deltarune, an NPC working at the local P"E"ZZA restaurant who's revealed in the second chapter to be him is referred to as "Blue Ears," but whether this is his actual name or merely a nickname is unknown.
Odd Friendship: With Burgerpants. Apparently, Burgerpants can't stand the Nice Cream Guy's lack of a sense of humor, but puts up with it because he gets free food out of it.
The Pollyanna: No matter how business goes, he's always willing to keep going. The only thing that can stop him is killing the Royal Guards.
Recurring Traveller: Appears in three different locations throughout the game to sell his wares.
Stepford Smiler: While he's definitely optimistic and shows a lot of emotion when he has a customer, it's easy to see how upset he is at his lack of success. Should you kill the Royal Guards, he'll drop the act entirely and become rather gloomy.
Throw the Dog a Bone: In addition to him being overjoyed when you buy his Nice Cream, sparing the Royal Guards will cause them to buy out his entire stock, encouraging him to stay in business.
Took a Shortcut: No matter how fast you go, he'll always be able to make it from mid-Snowdin to mid-Waterfall before you. Same thing goes for mid-Waterfall to the end of Hotland, though at least in this case the "shortcut" in question could be the elevator system.
Visual Pun: His design seems to reference an American brand of ice cream called Blue Bunny.
You Are Better Than You Think You Are: The messages on the Nice Cream wrappers (that display when used) are very uplifting.

Snowdin Shopkeeper

"Hello, traveller. How may I help you?"

A female rabbit monster who runs a shop in Snowdin.

Amazing Technicolor Wildlife: She is a rabbit with purple fur.
Exposed to the Elements: She seems comfortable wearing a tank top, despite living in the cold of Snowdin.
The Ghost: In the Genocide Route, her shop is empty and you can steal all of her wares and money. She has left behind a note saying, "Please don't hurt my family."
I Have a Family: On the Genocide Route, she leaves a note pleading with you not to hurt her family. You Bastard!
Leaning on the Fourth Wall: If you try to sell to her twice, she'll say, "If you're really hurtin' for cash, then maybe you could do some crowdfunding. I hear people will pay for ANYTHING nowadays," referencing the Kickstarter campaign that got the game funded in the first place.
Nice Girl: She chats pleasantly with you if you decide to talk to her.
No Name Given: Unlike the other shopkeepers in the game, her name isn't mentioned. In Deltarune, she is seen at, and probably owns, a diner named "QC's Diner" and is referred in the game's files as "QC", but wether these are her initials or her actually name remains to be seen.
Righteous Rabbit: She is an anthropomorphic rabbit who is very pleasant when in a conversation and even leaves behind a note telling the human to spare her family should they choose to go about and slaughter the locals of Snowdin.
Sweet Baker: If you buy a Cinnamon Bunny from her, she mentions that they're her own recipe.

Gerson

"Woah there!
I've got some neat junk for sale."

An old turtle monster who sells you items in Waterfall.

Adventurer Archaeologist: Certainly looks the part despite his age, with his magnifying glass and pith helmet. However, the only artifacts he has on sale are actually the equipment of the purple SOUL, or at least copies of them.
Cool Old Guy: He's pretty friendly and playful (assuming you're not in a No Mercy run at least), if only a bit senile.
Deadpan Snarker: On a No Mercy run, he falls firmly into this. Quotes include 'So you came... what a treat!' and 'Don't expect a discount'.
Did You Just Flip Off Cthulhu?: Since he possibly knows that the Fallen Human can't attack shopkeepers, he wastes no time berating you and giving you a multitude of You Bastard! lines while helping the survivors escape by buying them time.
"Facing the Bullets" One-Liner: When you try to sell him something on the No Mercy route, Gerson comments that he "wouldn't buy your chitzy garbage at knifepoint."
Humble Hero: In the No Mercy route, he claims he was never a hero, while simultaneously distracting you and buying time for others to escape to safe places. According to Ross and Barry, that's enough for him to count as a realistic hero.
Lampshade Hanging: If you try selling him anything, he'll point out how ridiculous that'd be, since he doesn't want MORE junk on his hands.
Meaningful Name: A somewhat convoluted one. His full name (Gerson Boom) is a reference to an infamous competitive Super Smash Bros. 64 match involving players Gerson and Superboomfan, where they spent roughly 50 minutes turtling each other, including a 23 minute timeframe where they didn't hit each other at all.
Medium Awareness: On the No Mercy route, he implies that he knows you can't attack shopkeepers, and is happy to charge you money and chat with you to buy more time for other monsters to evacuate.
Mr. Exposition: If you ask him about the Delta Rune and its significance. Notably he's the only one who refers to the symbol by name.
Named by the Adaptation: Deltarune gives his full name as Gerson Boom.
Red Baron: He was known as "the Hammer of Justice".
Retired Badass: Was once a hero much like Undyne is now. He was apparently called the Hammer of Justice. Though if you call Undyne outside of his shop, she mentions he's a legend for having been in the war because he survived it, not because he did anything special during it, which speaks leagues for how horrifically one-sided the war truly was.
Seen It All: His age helped a lot in his knowledge of history, since he's lived through most of it.
Shell Backpack: His adventurer shirt goes under his shell.
Signature Laugh: Wa ha ha!
Time Abyss: He's old enough to have been in the human/monster war.
Wise Old Turtle: He is a tortoise monster who has gone through many adventures in his lifetime and is more than happy to share the wisdom of what he has learned.

Temmie

https://static.tvtropes.org/pmwiki/pub/images/image_5.gif

"hOI!!!!!! i'm tEMMIE!!"

A type of cat/dog-like monster. They are all named Temmie (except for Bob).

Abnormal Allergy: Their only "attack" is that they trigger the player character's allergies when they try to cuddle. That's reasonable. Where it gets ridiculous is when you speak to one of them in the Temmie village, and she admits that she's also allergic to Temmies... including herself. She breaks out in hives immediately after saying that.
Author Avatar: Of the game's primary artist, Temmie Chang. In the credits, while most characters are listed as being created by someone, Temmie is credited as being Temmie (the artist) as opposed to being made by her.
Berserk Button: She seems to dislike muscles and flexing, to the point she would leave the battle if these are brought up.
Bizarre Taste in Food: Temmies love Temmie Flakes, which are just torn-up pieces of colored construction paper.
Broke the Rating Scale: After a patch in January 2016, using CHECK on Temmie will state her ATK and DEF are "Tem outta Tem."
Catchphrase: "hOI!! i'm temmie"
Cloud Cuckoolander: Easily some of the strangest monsters in the game. Their faces seem to be completely separate from their bodies, allowing them to move around the front of their head freely and even completely separate if you wait long enough when you're in battle with one of them and if you pay the Temmie Shopkeeper's college fee, she leaves her face behind while the rest of her moves offscreen.
Creator Cameo: Temmie is one of the artists who contributed to the game.
Cute Critters Act Childlike: They're Cloud Cuckoolanders of the highest degree, think humans are adorable and constantly try to pet them, and don't seem to understand the concept of money, the fact that you can't hatch a hard-boiled egg, or how to keep their faces from jittering away from their bodies.
Cute Kitten: A part-cat, part-dog monster that's all adorable.
Cuteness Overload: They love humans. Unfortunately, humans (or at the very least, the protagonist) are allergic to Temmie. One of their attacks when you encounter them is a stretching paw that gently touches your SOUL before retreating (which is to say, attacking by petting).
Cuteness Proximity: For humans. They go absolutely ballistic if they find you, gushing over how cute you are.
Department of Redundancy Department: Her Golden Ending title is... "Temmie". Both white and yellow titles, in fact.
The Ditz:
- A whole species of them. For instance, one of them is trying to hatch an egg, which upon examination turns out to be hard-boiled.
- The Temmie Shopkeeper is also the only shopkeeper you can sell items to, on the basis of just having poor impulse control. If you keep selling her items, she randomly decides that she wants to buy that specific item at a higher price while simultaneously complaining that she should save money for college instead but she never actually runs out of money to buy your items: as a result, you can fund her college solely by buying items from her and selling them back to her, implying that she already had all the money she needed to go to college but was too stupid to realize it.
- Encountering Temmies in battle can result in them forgetting their own attacks, or accidentally misspelling their name in the battle screen (as "Temmiy").
Enemy Summoner: Flexing at them during a battle will cause Aaron to appear, and Temmie to run away.
Expy:
- They're quite similar to the Mr. Saturns from EarthBound (1994) with their strange speech patterns, nonsensical village and alien demeanor along with a verbal tic in their dialogue. The difference between them is that the Mr. Saturns are actually geniuses and the Temmies are... absolutely not that.
- Also possibly to Nepeta of Homestuck as Aaron is to Equius, given the unique interaction they can have.
Extendable Arms: Her attacks involve her elongating her limbs to ridiculous and rather absurd lengths.
Genki Girl: If you encounter them in battle, they're constantly vibrating in place.
Good Is Dumb: The Temmies are really quite friendly, and are only even enemies because they think that humans are cute and want to pet them. That said, they're also a species of absolute dipsticks (except for maybe Bob and the Shopkeeper.)
Half-Dressed Cartoon Animal: Temmie wears a blue shirt, but no pants.
Hidden Depths: The Temmie Shopkeeper has the completely unexplained ability to know how many times you died, which very few characters have. See Ultimate Blacksmith below.
Inconsistent Spelling: The correct spelling is "Temmie", but "Temy" and "Temmiy" also pop up due to weirdness (the former being the spelling used for the Temmie Armor, the latter occasionally popping up in battle flavor text). "Tem" as shorthand seems to be consistent, at least.
Infinity +1 Sword: The Temmie shopkeeper carries the Temmie Armor, the second most powerful piece of armor in the game next to the Real Locket (which is not only locked to the Genocide route only, but is also completely useless against the final boss). However, not only does it start off at a high price of 9999G, and that only reduces the more you die (up to 25 times for a total of 750G), but you also need to purchase 'tem pay 4 colleg' for 1000G first. The Tem shopkeeper even lampshades this if you ask her about it:
if u lose a lot of battles, tem wil LOWER THE PRICE! so if you get to TOUGH BATTLE and feel FRUSTRATE, can buy TEM armor as last resort! but tem armor so goods, promise to only buy if you really needs it.
Intrigued by Humanity: Temmies LOVE humans and find them to be cute.
Karl Marx Hates Your Guts: Hilariously inverted. The Temmie shopkeeper seems to have no concept of the value of money — she'll pay much more for some items than other items which are much stronger, and you can sell her own items back to her (or items sold by the nearby shopkeeper Gerson) for a higher price than you paid for them.
- Played straight in the Genocide route, however; she simply tries to scam you with an overpriced Temmie Flake instead of letting you unlock the Temmie Armour.
Leitmotif: "Temmie Village" and "Tem Shop", which are remixes of "Dogsong".
Mercy Mode: Depending on how much you die, the Tem Armor will drop down in price, down to 750G for 25 deaths.
Mix-and-Match Critter: They are essentially a hybrid between dogs and cats.
Money Dumb: Money seems to be no object to them. The Temmie shopkeeper will endlessly buy items from you, including ones she just sold you, yet still needs your help to fund her college fees.
Muscle Angst: Flex in front of one and she'll remark "muscles r ... NOTCUTE!"... Then Aaron will pop up and Temmie will simply run off because she can't stand him and his muscles.
Obfuscating Stupidity:
- The shopkeep Temmie speaks in proper English if you agitate her by refusing to sell her an item she really wants twice in a row.
  Temmie: You will regret this.
  (...)
  Temmie: Is this a joke? Are you having a chuckle? Ha ha, very funny. I'm the one with a degree.
- On a No Mercy run, the Temmie shopkeeper will try to scam you with an absurdly expensive (and useless) Temmie Flake instead of offering to pay for college so you can obtain the Temmie Armor, implying that despite being Temmie, they're at least perceptive enough to realize helping you is an awful idea.
One-Gender Race: All of the Temmies in the game are referred to as female.
O.O.C. Is Serious Business: Played for laughs with the Temmie shopkeeper if you refuse to sell her something that she's offering you extra money for.
- The Genocide run has her trying to scam you with an expensive Temmie Flake instead of giving you a chance to buy the Temmie Armour. Even she would know better than to sell a murderer something useful.
Odd Name Out: They're all named Temmie. Except for Bob.
Painting the Medium: Their dialogue is filled with bizarre spelling, capitalization, and punctuation errors that Funetik Aksent alone can't account for.
Planet of Steves: All of the Temmies are named Temmie, with the exception of one named Bob.
Playful Cat Smile: Almost always have a cat smile plastered on their face, which is rather fittingly, given the species wears The Ditz hat as a whole. Most prominent on the Temmie Shopkeeper◊.
Puff of Logic: The Temmie that is allergic to itself doesn't show any signs of a reaction until it tells you as much, then it immediately breaks out in 'hOIVS'.
Purposely Overpowered: The Temmie Armour gives the user +20 defence, longer Mercy Invincibility, +10 attack, and heals 1 hitpoint every other turn. Temmie even knows it's so good, she only recommends using it if the player is currently struggling on a boss, and each death lowers the price.
Rubber Man: Their attacks consist of stretching their limbs to either 'pet' you or walk around with the chance you'll bump into their legs.
Screw This, I'm Outta Here: One way to defeat Temmie is by bringing the attention of Aaron by flexing, which causes her to leave the battle out of distaste.
Self-Deprecation: For artist Temmie Chang. She was put in the game... as an entire species of complete idiots.
Tastes Like Friendship: In battle, Temmie becomes instantly spareable if you give her Temmie Flakes.
Trademark Favorite Food: Tem Flakes. Which are made out of construction paper.
Trauma Button: Don't flex in front of one, especially if you have muscles, or it'll run away frightened.
Ultimate Blacksmith: Paying for the Temmie shopkeeper to go to college will allow her to create for you the single best armor in the game. It starts out ridiculously expensive, but the price goes down every time you die.
Uplifted Animal: One Temmie in the village, who goes by the name of Bob and speaks in an intelligent manner.
Verbal Tic: A few of the words in their dialogue are puns of the word "hoi" ("bOI!", "hOIVS!")
Voice Grunting: A cat-like chattering noise, which changes pitch at random to emphasize their odd speech patterns.
We Buy Anything: The shopkeeper will buy anything from you, including items that she just sold to you a few moments ago, and often at a higher price than you bought it for.
Wingding Eyes: Landing a fatal blow on Temmie results in her eyes turning into 2 X's before she turns to dust.

Bratty and Catty

https://static.tvtropes.org/pmwiki/pub/images/brattycatty.png

"Hey! Check it out!"

"Yeah! Check it out!"

Two trendy monster girls who hang out in an alley and sell you stuff.

Affably Evil: They're just SO hyped for the destruction of humanity! They seem embarrassed about it in the epilogue, if the player confronts them about being a human.
Amazing Technicolor Wildlife: Catty is a bright purple cat monster.
Big Beautiful Woman: Catty is noticeably plus-sized, and Burgerpants refers to her as a “hot chick” at at least one point.
Buffoonish Tomcat: Catty is a Gender Inverted version of this trope. She’s an airheaded Valley Girl with a plump body type who loves Glamburgers.
Childhood Friends: They were friends with Alphys when they were younger, though Alphys is enough older than them that they describe her as a "big sister." However, they haven't hung out with her in awhile, since Alphys is now the Royal Scientist.
Cute Little Fangs: Catty has them. Well, she is a cat.
The Dividual: As they are the only shopkeepers that work together, they are only seen together. Aside from visual difference and a few odd personality quirks (Bratty is a bit more sensible and Catty a bit more energetic) there isn't much that distinguish them.
The Ditz: Catty once mistook the Annoying Dog for a cat. When Bratty tries to tell her it's a dog, Catty's answer is "DOGS ARE JUST FIRM CATS!!!!"
Dub Name Change: Bratty is known as Aligatty in the official Japanese localization.
Dumpster Dive: They get all their goods from the trash.
Fangirl: Of Mettaton, to the point that Catty tries to pay you to get Mettaton to sign her butt. They also go off on a long spiel about both being married to him, and he just doesn't know it yet.
Fat and Skinny: Implied in their shop sprites. Catty's the fat, while Bratty's skinny.
Foreshadowing: Talking to them about Mettaton will bring up some very interesting facts about him they've noticed. Such as Mettaton always acting like being built was his idea and how he always treats Alphys like an old friend.
Furry Confusion: Comes up in the epilogue. Catty expresses her desire to own a pet cat, while Bratty expresses her desire to eat one. But Bratty's just joking. Allegedly.
Furry Reminder: The canceled Undertale alarm-clock app reveals that Catty once broke into Alphys' house to use her space heater. Of course, cats love warm things and places.
Gameplay and Story Segregation: Some of their dialogue involves them asking you to get them Glamburgers, and they even get excited if they notice you're carrying one. However, you can't actually sell them anything, so it's impossible to give them Glamburgers.
Green Gators: Bratty is a mint-green alligator monster.
Heterosexual Life-Partners: Despite both loving Mettaton, Catty offhandedly mentions "[she] doesn't want to have a dream without [Bratty] in it," and they seem to imagine being married to him together.
Hypocritical Humor: Trying to sell them something while you have a Glamburger in your inventory triggers this conversation.
Catty: Oh my God. Is that a Glamburger? OH MY GOD!!! GIMME!!!
Bratty: God, Catty. Try to have some self-control.
Catty: Sorry...
Bratty: 'Cause they OBVIOUSLY brought that Glamburger for ME.
Catty: NO WAYYY!!!!!
Like Is, Like, a Comma: To go with their Valley Girl accents.
Meaningful Name:
- Catty's a cat. Go figure.
- Both of them have bratty Valley Girl mannerisms, and one of them is even named Bratty.
- Their species, too. See Stealth Pun below.
Non-Mammalian Hair: Bratty, an alligator monster, has blonde hair styled in Regal Ringlets.
Not So Above It All: While Bratty is a bit more sensible than Catty... it's not by much. See Hypocritical Humor.
Ship Tease: With each other, but Catty also mentions that though Burgerpants is weird, she also thinks he's "kind of cute".
Signature Laugh: MEOW-MEOW! Incidentally, this is the cat sound from the music composition game in Mario Paint.
Skewed Priorities: On the No Mercy path, the two leave a lengthy note with both of their own comments to the protagonist insulting them and telling them not to take their stuff... because they didn't want their pens to go to waste. And all the while, Alphys was trying to get them to evacuate.
Stealth Pun: Together they are an Alley-cat and an Alley-gator. They are also V-alley girls.
Trademark Favorite Food: Glamburgers. If you choose the "sell" option, they ask you to get them some, and they get excited if they notice that you are carrying one.
The Thing That Would Not Leave: The Undertale alarm-clock app reveals that, when Alphys bought herself a new space heater to keep herself warm in the winter, Catty broke into her house to use it. She brought oranges to bribe her with (that she had already ate, leaving just the peel.)
Verbal Tic: "Totally!"
Valley Girl: With a touch of Boston, to judge by their use of "wicked" to mean "very".
Wingding Eyes: They both end up with hearts for pupils whenever they talk about Mettaton or Glamburgers.

Burgerpants

https://static.tvtropes.org/pmwiki/pub/images/image20.png

"Don't live like me. I'm 19 years old and I've already wasted my entire life."

A long-suffering employee at the MTT-Brand Burger Emporium. Has a dour outlook on life.

Achievements in Ignorance: In the No Mercy route, he has no real idea what's going on or how dangerous the protagonist is; he still manages to survive meeting them (and even mocks them to their face) simply by virtue of being in a shop and therefore invulnerable. Unlike Gerson, he has no idea this is how it works, remaining there because he doesn't realize everyone is evacuating.
Affectionate Nickname: If the player gets friendly with him, he'll regularly call them "Little Buddy." Inversely, if the player is doing the genocide route, he'll call them "Little Weirdo."
Apathetic Clerk: Burgerpants keeps up a paper-thin smiling facade until you buy something from him... then drops it for a Deadpan Snarker attitude and a complete apathy towards his job.
Be Careful What You Wish For: He used to actually want to work with Metatton. Now he does, and he couldn't be unhappier. He even quotes the name of the trope word for word.
Berserk Button: Before he's talked into dropping his customer-service-face, trying to sell him an item will give him an internal Freak Out, and trying a second time will get him to outright shout "WHO DO YOU THINK YOU ARE?", one of only two times he shows the player character outright animosity. Part of the reason this tweaks him so bad seems to be a lack of control over the situation; trying it after he drops the facade gets only a casual suggestion to ask Bratty and Catty instead.
Boss's Unfavorite Employee: Mettaton may not be the best manager, but he's generally a Benevolent Boss to his employees... aside from Burgerpants. He even made a whole album dedicated to telling Burgerpants how bad at his job he is.
Burger Fool: The foremost employee in MTT Burger, which plays this trope to a T, and the victim of every single stereotype related to them. In fact, it appears that he has fully resigned himself to this fate.
Burgerpants: I'm 19 years old and I've already wasted my entire life.
Butt-Monkey: He wants to be a movie star, but without any talent or experience he found himself working at a fast food joint with incompetent management to make ends meet. The misfortune kept piling up from there, from losing his pants while trying to sneak Glamburgers out of the restaurant to Mettaton making a musical album about how bad he is at his job.
Cartoon Creature: He looks like a mix between a cat and a bear, and due to his constantly changing sprite, sometimes he looks more like one than the other.
Chubby Chaser: Refers to both Catty and Bratty as "hot chicks," the former of which is visibly overweight. Proving that, at the very least, plumpness isn't a dealbreaker for him.
Cigarette of Anxiety: He regularly lights up a cigarette when talking to the player, no doubt to relieve the stress of his job.
Comedic Underwear Exposure: How he got his Embarrassing Nickname: he tried to sneak some Glamburgers out of the restaurant for Bratty and Catty by hiding them in his pants, only for Mettaton to startle him and cause his pants to fall down.
The Cynic: Completely resigned to being stuck in his terrible job forever, thinks friendship is just a way for attractive people to enslave you, generally has nothing good to say about anything or anyone... He has a bad case of this. The only thing that keeps him going is the hope that the barrier is broken and that he can leave the fast food business behind him to pursue his acting career.
Embarrassing Nickname: "Burgerpants" isn't his real name. He got stuck with the moniker after an attempt to smuggle Glamburgers to Bratty and Catty ended with the burgers making his pants fall down.
Expressive Accessory: The M on his hat changes along with his sprite. Sometimes it's an M, sometimes it's a squiggle, and sometimes it's a W.
Gonk: The result of being animated with a John Kricfalusi-esque attachment to emotion over sticking to the model gets him doing some hilariously ugly expressions none of the other characters even come close to making, not even Flowey. It's also because Toby didn't change his "terrible concept art".◊
Hypocritical Humor: When you tell him that Bratty and Catty want him to stop acting like it's their fault he got his nickname so they can become friends, he claims that friendship is just a way for attractive people to make you their slave. Cue Beat.
Burgerpants: So, uh, what time would they wanna hang out?
Jerk with a Heart of Gold: Downplayed; His disdain towards Mettaton is justified, his humiliation from both his employer and others makes his pessimism very understandable, and he doesn't actively hurt anyone... but it can't be denied Burgerpants lets his cynicism get the better of his judgement, and he misblames the alley girls and imparts unhealthy advice towards the young protagonist because of this. That being said, he really does seem to want to help them avoid making his mistakes, and his Affectionate Nickname for them only further proves he's got a genuine soft spot towards the child and appreciates talking to them. He comes off as less of a jerk than he does someone who needs better company.
Non-Standard Character Design: He wouldn't look out of place in an episode of Ren & Stimpy. His face, and the rest of his body for that matter, don't stick to one shape between his different expressions.
Only Known by Their Nickname: He got stuck with it after an attempt at smuggling some Glamburgers for Bratty and Catty got him startled by Mettaton and his pants dropped when trying to pick up some burgers that fell out, which caused all the other burgers in his pants to spill out.
Playing a Tree: The credits show him as a bush in a play Mettaton is performing.
Self-Deprecation: If you try to name the fallen human "BPants" at the beginning of the game, he says "You are really scraping the bottom of the barrel."
Slept Through the Apocalypse: He's completely unaware of the evacuation in the No Mercy run. Upon being told this, he blows it off. When told everyone is dead, he asks if that means he doesn't have to work today before being similarly unconcerned. Hilariously, this cynicism keeps him alive in the long run since there's no way to actually fight someone in the shop menu, so he can't be killed as long as he stays there.
Small Name, Big Ego: He conveys himself as a jaded, worldly person with a great actor's potential, held back only by his miserable job and boss. While his aspirations are sincere and some people (namely Mettaton) could really stand to treat him better, it's shown his own pessimism is holding him back at least as much, rejecting and assuming badly in others seemingly wholly from fear. The 'wisdom' he tries to impart to the protagonist is just his unhappy and self-defeating beliefs, such as how the only way to get through life is to lie to yourself, and that attractive people only ever want to take from you. When you convince Catty and Bratty to invite him to the dump, it seems to be largely from pity and free food (though Catty is genuinely excited, and Bratty intended to share with him before).
Smoking Is Not Cool: A habitual smoker who's also a miserable cynic stuck with a job he hates.
Suspiciously Specific Denial: In the No Mercy route, he's aware that the protagonist is killing everyone, but he continues his job as if nothing is wrong, even when questioned about everyone leaving.
Threat Backfire: Attempting to threaten him on the No Mercy run causes him to spout this gem:
Burgerpants: I can't go to hell. I'm all out of vacation days.
Throw the Dog a Bone: He finally gets to realize his original dreams in the True Pacifist Ending, in which he's seen onstage with Mettaton, Napstablook and Shyren at a concert.

Other NPCs

Grillby

...

A quiet fire monster who runs Grillby's, a popular bar in Snowdin. Everybody comes to Grillby's.

The Bartender: He's the owner and bartender of Grillby's.
The Blank: His only facial features are his glasses; he doesn't even seem to have eyes.
Elemental Embodiment: His entire body is made of orange flame, making him stand out a bit in Snowdin.
Obsessive-Compulsive Barkeeping: His idle animation — almost his only animation — is him polishing a glass.
The Quiet One: Almost never speaks; a monster in the bar usually translates what she thinks Grillby means, but she admits she has no idea if she's anywhere close. In the True Pacifist Ending, he'll tell you that you did a "good job.", but that's about it.

Monster Kid

https://static.tvtropes.org/pmwiki/pub/images/93066cdd_9ee3_4907_b722_e410ba702e57.jpeg

"Yo."

A monster who follows you from Snowdin.

Accidental Hero: In the neutral/pacifist run, throughout the human child's trip through Waterfall, Monster Kid frequently saves the human child from getting caught or killed by Undyne just by being at the right place at the right time.
Ambiguous Gender: Undyne refers to them only as "they" in a phone call if you save them on the bridge in Waterfall. Toby Fox did refer to them as "he" in the original version of the art book, but this was changed in a later version. They also refer to themself with the typically-male pronoun "ore" in the official Japanese translation.
Armless Biped: Appears to be this: they often trip but pull themself back up without the use of arms or any other kind of appendage and if you don't pick up an umbrella during the rainy segment in the Waterfall, they remark that it seems that you can't hold one either. Their tarot card also shows them running through Snowdin holding a popsicle in their mouth.
Broken Pedestal: If you saved them from falling from the bridge, they say they do not think Undyne is that great anymore, and that they found themself a new idol, likely Papyrus.
Character Shilling: They do this with Undyne, telling the player how cool and awesome and righteous she is constantly as you walk through Waterfall. Though it turns out to be true, the player may not initially agree since Undyne is trying to kill them at the time.
Chekhov's Gag: After every encounter, they will trip as they run off, to the extent where it becomes a Running Gag. This turns out to set up for them to fall off a bridge, barely hanging on to the edge near the end of the Waterfall. They survive because even if you choose not to help, Undyne will rescue them.
Comically Missing the Point: It takes them a remarkably long time to figure out that you are a human.
Go Through Me: If you save them on a Neutral/Pacifist run, they stand between you and Undyne and shakily states this trope word for word. On No Mercy, they stand in your way because they won't allow you to hurt anyone else.
Hero-Worshipper: Almost all of their dialogue is gushing over how awesome Undyne is. During the Playable Epilogue, they realize that Undyne might actually just be kind of a jerk, and starts gushing over Papyrus instead.
His Name Really Is "Barkeep": According to Toby, their name really is 'Kid'.
Improbable Infant Survival: In No Mercy, the fallen child attempts to kill them when they get in the way, only for Undyne to save them. But, given what happens at the end of every No Mercy run, they're probably not doing better than the rest of the world.
The Klutz: They frequently trip and fall on their face, presumably because they don't have arms. In their tarot card artwork, they have a bandage on their head.
Look Behind You: If you've already seen their speech on No Mercy, this is how it is shortened on future attempts; they start their speech, but they turn around and say "What? Look over here? What for—" before the game goes to the battle screen for the Undyne fight.
Lovable Lizard: MK is a monster who resembles a lizard and is by far one of the most endearing characters you'll meet on your journey.
Morality Pet: Their actions in a No Mercy run imply that they're trying to be this to the player character, still doubting claims of your evilness, and the resultant Go Through Me gets Undyne killed on the spot if you don't spare them. She gets better pretty quick, though. Much better.
My God, What Have I Done?: Upon seeing Undyne mortally wounded, they clearly believe they are responsible for them risking her life like that even try to apologize to her. However, Undyne easily forgives them and then orders them to leave which they do without a second thought.
Nice Guy: A good-hearted kid who would defend you from Undyne if you save them on a Neutral/Pacifist run, or stand in your way so that you won't hurt others on a No Mercy run.
Nice Job Breaking It, Hero: In a No Mercy run, they follow you around while Undyne is hunting you, and at a few instances, Undyne gives up on a chance to slay you so as to remove them from the area for their own safety. If you complete a No Mercy run, then it's partially because the Monster Kid got in the way.
Running Gag: Literally! When they break out into a run, before leaving the frame, they'll trip and fall flat on their face before getting right back up and continuing their run.
Shoo the Dog: When they finally figure out you're a human, they ask you to be mean to them so they can feel okay about hating you, since your races are enemies. If you refuse, they'll reluctantly insult you instead. If you choose to insult them, they laugh, saying that their sister calls them that all the time, so they have to insult you instead anyway.
Shout-Out: Their design resembles a Scraggy.
Verbal Tic: "Yo!"

Onionsan

"Hey... there... noticed you were... here..."

An enormous aquatic monster who is very lonely.

Ambiguous Gender: Their gender is never stated in the game.
Animesque: While some of the game artwork is this to a degree, they are the most prominent (their eyes in particular), and the inexplicable "san" at the end of their name.
Funny Octopus: Onionsan is a Giant Squid-like creature who initially seems threatening... until they reveal their onion-shaped head and comical Animesque facial expressions.
Luminescent Blush: Sports some pink blush when they look optimistic.
Mood-Swinger: They change moods very quickly, with expressions ranging from wide-eyed optimism to barely-holding-in-a-panic-attack.
Punny Name: Not Onionsan themself, but the name of a band they wants to put together is called the Red Hot Chibi Peppers. They've only thought of the name.
Shrinking Violet: Gives off this vibe.
Stepford Smiler: Has a huge smile on their face every time you see them and greets you happily whenever you walk by, despite very clearly being distressed about the lowering water levels of Waterfall. Brief cracks in their facade suggest they're actually very depressed.

Annoying Dog

https://static.tvtropes.org/pmwiki/pub/images/tobyfox.png

(He doesn't know what to say.)

A recurring NPC that exists to be lazy and annoy everyone. Also, he's Toby Fox, creator of Undertale. Resembles a Samoyed, a real life dog breed.

Achievements in Ignorance: If you beat the credits, opening the Mysterious Door, you can find the Annoying Dog’s hideout, where it apparently accidentally programmed an entire game through a program that translated its barks.
Ambiguously Human: Make that ambiguously canine. He's a dog monster that can absorb items through his skin and leaves behind a "dog residue", which can be variously described as a shed husk, shiny trail, webbing, unwashed dishes, glowing crystals, or an unfinished jigsaw puzzle. Then again, he lives in a world of monsters, implying he is not an actual dog.
Author Avatar: Appears in the Greenlight trailer and the hidden developer room as Toby's avatar.
Author Powers: The Annoying Dog seems to have these, though he only ever uses them to appear at times and places that are most inconvenient for Papyrus - such as invading the battle screen and stealing his "special attack".
Darkhorse Victory: In the Neutral ending when all major bosses are dead, but no enemies are, the Annoying Dog is heavily implied to become king, simply because nobody is willing to challenge him for it. At least his laziness makes for a good ruler... somehow.
Diabolus ex Machina: Pretty much its MO. If something inconvenient, annoying, or unfortunate has to suddenly happen to the Protagonist or one of their friends to make their day worse, it's often the Annoying Dog's fault. Examples include stealing Toriel's phone so you can't call her for assistance, swiping Papyrus' bones so he can't use his Special Attack on you, and absorbing the Legendary Artifact so the Protagonist can't have it. Perhaps the biggest one, though, is him stopping Hard Mode simply to teach the player to accept that it’s over.
Leitmotif: "Dogsong", while more often used in the game for dogs in general or Trolling moments, is seen as the Annoying Dog's theme, and pops up almost every time it appears. The song plays when Sans is talking to the player in the Neutral run when a dog becomes king, which heavily implies it was the Annoying Dog himself.
Mythology Gag: Possibly unintentional, but how it managed to program a whole indie game by barking into a translator by accident may remind certain fans of how Toby himself composed Megalovania.^note
Recurring Extra: The Annoying Dog, Toby's Author Avatar that appears all throughout the game as a lazy, greedy and stupid dog. He even shows up at the end of Hard Mode.
Running Gag: The Annoying Dog frequently shows up just to cause trouble, usually for Toriel and Papyrus. It steals Toriel's cellphone multiple times, and eats Papyrus' ultimate attack and bone collection.
Self-Deprecation:
- It's described as lazy and annoying, and generally does nothing but be a nuisance around everybody. Toby even calls himself a shitty dog when posting the news about his own game having higher ratings than Hideo Kojima's then latest game on Tumblr.
- Within the non-failsafe Developer's Room, examining the Annoying Dog's computer reveals "most bad posts come from him". The Annoying Dog is the game's Author Avatar.
Shoo Out the Clowns: It usually appears sleeping on the screen during the game's ending. However, it will be absent if you have previously completed a Genocide run.
Sitcom Arch-Nemesis: With Papyrus - he is always stealing Papyrus' bones, while Papyrus tries to use Annoying Dog in one of his puzzles against the player.
Suddenly Voiced: The Annoying Dog actually talks at the end of Hard Mode to declare it over.
Troll: The Annoying Dog lives for it. All of its appearances involve messing with the characters or the player themselves, and "Dogsong", its theme, is associated with trolling moments such as Sans' I Surrender, Suckers in the No Mercy run. In the Developer Room, it's revealed that almost every troll-post online was made by this dog.
Trolling Creator: The above combined with being an Author Avatar makes him (and Toby Fox) an In-Universe example. How many game designers personally show up in the middle of the game to screw with their own characters and the player?
The Unfought: No matter how often you see the Annoying Dog nor how much it might annoy you, none of the times where you see it allow it to be fought. The one time you directly interact with him, the games states that his rug needs to be "patched" to fight him. When the game was patched in January 2016, dialogue was added to show that a single patch wouldn't work since the holes are growing.
Wink "Ding!": If you open the drawer in Undyne's house, the Annoying Dog will be revealed to be inside. It winks with a ding before closing the drawer.

River Person

"Tra la la."

A boat-master who takes you from town to town.

Ambiguous Gender: "I am the riverman. Or am I the riverwoman...? It doesn't really matter." While this is the case for plenty of characters in the game, the River Person is the only one who lampshades it. Is named "riverman" in the game files though.
Black Cloak: The River Person wears a cloak with a hood that conceals any identifying features.
Catchphrase: "Tra la la..."
Cool Boat: It's normally a bland piece of wood, but occasionally and randomly it will turn into a dog-headed boat that moves by levitating and running over the water.
Dark Is Not Evil: Wears a black hooded cloak and their face (if any) is covered entirely in shadow, yet they're simply another friendly and socialable monster — one who serves as public transportation, at that.
Don't Fear the Reaper: They look like the Grim Reaper with the mysterious hooded cloak, but they're pretty personable and helpful, all things considered.
Expy: Their character seems to be a Shout-Out to Kapp'n from Animal Crossing, as a wise boat-master who imparts random tidbits of trivia in song. Also resembles Charon, the ferryman of the river Styx in Greek Mythology.
The Faceless: Their face is obscured by a hood.
The Ferryman: Fits perfectly the classical depiction of this trope, being a hooded figure who allows the player to travel from place to place using their boat.
Hidden Depths: They seemingly know that Flowey is neither a monster nor a human. And while it's mostly speculation at this point, one of their possible lines implies that they know about Dr. Gaster.
"Tra la la. Beware of the man who speaks in hands."
In the Hood: They always wear their hood up, which contributes to how mysterious they are.
Nerves of Steel: They're the only character that the Fallen Child directly interacts with during a No Mercy playthrough who doesn't react to them in the slightest despite everything that's happening around them, even though they don't have the innate protection against being attacked that shopkeepers like Gerson and Burgerpants do. Maybe the protection extends to all fast travel services as well?

Mentioned

Rudolph Holiday

An old friend of Asgore's who has died from old age before the events of the game.

Affectionate Nickname: Asgore referred to him as "Rudy."
The Ghost: Is mentioned in the unused Alarm Clock app dialogue, but is never seen in person, not even in flashbacks.
Posthumous Character: Has died of old age before the events of the game.

Rudolph's daughters

The daughters of Rudolph. In Deltarune, they're known as Noelle and Dess Holiday, though it's been mentioned that Rudolph had many daughters in this continuity.

The Ghost: Are mentioned in the Xbox version of the game and in the unused Alarm Clock app dialogue, but are never seen in person.
Vague Age: Whether they're as young as Frisk or are adults living on their own hasn't been stated.

Characters / Undertale - Other Characters

Mini-bosses

Napstablook

Snowdin Canine Unit

Mad Dummy/Mad Mew Mew

RG 01 & RG 02

So Sorry

Muffet

Shopkeepers

Nice Cream Guy

Snowdin Shopkeeper

Gerson

Temmie

Bratty and Catty

Burgerpants

Other NPCs

Grillby

Monster Kid

Onionsan

Annoying Dog

River Person

Mentioned

Rudolph Holiday

Rudolph's daughters

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Index

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Characters / Undertale - Other Characters

Edit Locked

Mini-bosses

Napstablook

Snowdin Canine Unit

Mad Dummy/Mad Mew Mew

RG 01 & RG 02

So Sorry

Muffet

Shopkeepers

Nice Cream Guy

Snowdin Shopkeeper

Gerson

Temmie

Bratty and Catty

Burgerpants

Other NPCs

Grillby

Monster Kid

Onionsan

Annoying Dog

River Person

Mentioned

Rudolph Holiday

Rudolph's daughters

Previous

Index

Next