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For other versions of Underswap, see Underswap (disambiguation).

Underswap MH is an Underswap take made by Miss Holoska. Rather than the characters completely or mostly keeping or swapping personalities, they're a balanced mix of both. Generally, characters’ roles, surface-level personalities, ambitions/goals, and jobs are swapped as expected, but their original personality traits, morals, interests and -if possible- abilities are kept the same.


These are the currently confirmed swaps:

  • Sans - Papyrus
  • Undyne - Alphys
  • Toriel - Asgore
  • Frisk - Chara
  • Flowey - Temmie
  • Mettaton - Napstablook
  • Asriel - Monster Kid
  • Muffet - Grillby
  • Burgerpants - Nice Cream Guy
  • Bratty & Catty - Royal Guards 01 & 02
  • Canine Unit - Snowdin Rabbits (which dog swaps with which rabbit is still unknown)
  • River Person - Gerson
  • Onionsan - Bird That Carries You Across A Disproportionally Small Gap

The Swap version of Miss Holoska's monstersona Snoey exists as an additional character, rather than replacing the Annoying Dog like most author self-inserts.


  • They have 2 stripes on their shirt.
  • They're less silent than UT Frisk, aside from genocide, where they are completely silent.
  • They're a sassy kid with issues.
  • Rather than =), -_- shows up in genocide when encountering a monster.
  • Their Halloween costume is Pumpkaboo, the best Pokemon according to Miss Holoska.


  • They were younger than Chara at their time of death.
  • They're a ghost floating around Chara.
  • They often talk outside of checking things.
  • They only have one stripe on their shirt.
  • They are too young to understand confusing science jokes.
  • They don't like the genocide route.
  • Their Halloween "costume" is a ghost/zombie/zombie ghost?


  • Uses she/her pronouns as a fake identity.
  • She talks in the Temmie way, though act like Flowey.
  • Drops the Tem speech when serious, but never lets anyone see her drop the act.
  • Her body is Fangamer's Temmie Plush.
  • She can still stretch out her legs.
  • She do not trust Sans but pretends to be friendly around him.


  • He originally declared war on humanity, but Toriel talked him out of it. Rather than facing up to the anger he instilled in his people and calling it off, he left for the Ruins.
  • He's less reclusive than classic Toriel, often walking around and talking to the monsters in the Ruins (some can't help to feel a bit intimidated by him though).
  • He doesn't keep the door shut in case Chara wants to back out of their plan.
  • His friendship with Papyrus goes further than the door, and Papyrus often visits him in person.
  • He has 2 different colored eyes.
  • He does not have a grudge towards Toriel.
  • His nickname outside the AU is Dandelion.
  • His Halloween costume is a wizard.


  • He can come off as awkward at first, but around familiar company, he becomes much more of a charming performer.
  • Toriel is his best customer.
  • He actually gets killed in genocide, unlike Napstablook in Undertale.
  • His Halloween "costume" is a ghost/zombie/zombie ghost, just like Frisk


  • He still is the younger brother.
  • His stats are lower than in Undertale due to a lack of regular training, however, they're not as low as Sans' in Undertale.
  • He only sleeps when he is completely bored, which isn't often. He often has things keeping him occupied even when it doesn't seem like it.
  • He likes good puns, but not Sans' bad ones.
  • He doesn't smoke, instead, he noisily slurps single spaghetti noodles all the time to annoy Sans.
  • He cooks spaghetti for himself but isn't much of a better cook than UT Papyrus.
  • He still has a passion for puzzles and is responsible for most of Snowdin's ones, but he makes them just for fun rather than for his job like Sans.
  • He has social anxiety rather than depression (even though it's debatable if Sans had depression in Undertale).
  • He is Undyne's lab partner.
  • He has a sock collection like UT Sans and never wears matching pairs.
  • His eyes glow yellow and cyan and shows it on more occasions than serious battles. He has no orange attacks, like in Undertale he still uses light blue ones.
  • In genocide he still gets killed in Snowdin.
  • His nickname outside of the AU is Noodle.
    • The Outer version's is Space Noodle.
  • His Halloween costume is his brother's outfit.


  • He still is the older brother.
  • He used to have 1 HP like UT Sans but raised his stats by training.
  • His stamina hasn't caught up with his increased stats and he easily exhausts himself from constantly rushing around. He naps less often than UT Sans, however.
  • He loves bad puns because he believes puns don't need to be "good", they just need to make people happy.
  • He calls himself "The Sans-ational Sans" for the sake of a pun.
  • He shares UT Sans' observation skills.
  • He likes standing on bones to match his brother's height, and this gave him an incredibly good balance. He also likes sitting on floating bones, sometimes hanging upside-down.
  • His eyes glow blue and green.
  • He still leaves socks lying around, but by accident.
  • He's still very capable to be gross, he just has some shame about it.
  • He hates making promises, as he dislikes having obligations to people and prefers to do things as, when and because he wants to, but if he makes one he keeps his word.
  • His hangout is at Muffet's rather than in his room.
  • He does not trust Temmie but pretends to be friendly around her.
  • He has a crush on queen Toriel.
  • He still is the genocide final boss.
  • His nickname outside of the AU is Neptune.
    • It used to be Blueberry until Miss Holoska realized the name was associated with the cringy fanonswap Sans.
    • The Outer version's is Neptunite.
  • His Halloween costume is a black cat.


  • He tries to be a friendly burger vendor, but he still is, you know, Burgerpants.
  • He's annoyed that the rabbit guard doesn't buy his stuff, as they either think he's a predator or just find him a weirdo.
  • He hates being wet, as he's a cat. Thus, he hates Waterfall.


  • She is quiet and stoic towards new customers, but immediately sweet and welcoming once she has the money.
  • She sells carrot cake to the Rabbit Guard to get more money from them.
  • She doesn't give discounts.


  • He often gets kicked out of Muffet's for smoking dog treats.
  • He likes Muffet's as he can see the spiders moving.


  • She doesn't like herself under the explosive personality but has more confidence in her abilities than in Undertale. She lives by the motto of "Fake it till you make it".
  • She shares UT Alphys' analytical mind and is good at focusing on situations and quickly figuring out how to deal with them.
  • She stutters when speaking normally, but trained it out of her shouting voice.
  • While her right eye is scarred, she still can see with it.
  • Unlike UT Undyne, she eventually manages to be honest about not wanting Sans in the guard but helps him train.
  • She is still a member of Happstablook's human fan-club the Underground's shipper extraordinaire.
  • Rather than playing piano, she listens to anime songs at max volume.
  • Toriel is a motherly figure to her.
  • She doesn't have an Undying form and doesn't fight in genocide.
  • Her nickname outside of the AU is Axe.
    • The Outer version's is Axeteroid.
  • Her Halloween costume is a spooky Mew Mew cosplay.


  • He's Asgore and Toriel's nephew rather than their son. His parents are dead.
  • In Genocide, he's less oblivious than Monster Kid but tries to convince Chara to be kind.
  • His Halloween costume is a fallen angel.


  • Most people feel things ranging from slight discomfort to fear in Flowey Village, aside from Papyrus. After all, they're just a bunch of happy smiling faces calling you their best friend.
  • The Bob equivalent is basically canon Flowey personality-wise and hates everyone. One of the others usually quickly shuts him up however.
  • The shopkeeper Flowey only has 5 petals like the non-sentient golden flowers (this might change however) and sells Friendliness Pellets.


  • Her attack is still high, but not as high as in UT due to less and less intensive training.
  • While she seems quieter like Alphys in Undertale, her approach to science is much more like UT Undyne's "leap headfirst into it and see what happens". She' not stupid about it though, just (over)confident and enthusiastic.
  • When doing science or cooking (which are honestly indistinguishable from each other sometimes) with Papyrus, she acts much more like UT Undyne.
  • She doesn't stutter but sometimes trips over her words.
  • Not as crushed by depression about the Amalgamates, as she is in denial and believes she still can find a way to save them.
  • She lost her left eye, and made a fake eye to make it look normal, but she only has vision in her right eye. Her glasses with hologram screens have the controls built into the left side because of this.
  • She still plays piano and is better at it than UT Undyne due to her being more skilled in precise tasks.
  • She laces her spears with dangerous chemicals to give them special effects.
  • She still becomes Undyne the Undying in genocide, before which she hunts Frisk down in Waterfall rather than Alphys.
  • The replacement for Mew Mew Kissie Cutie as the anime Undyne likes is an anime called Sword GF. Alphys still likes Mew Mew, however.
  • Her nickname outside of the AU is Sci-Fi (Science Fish).
    • The Outer version is Sky-Fi.
  • Her Halloween costume is a vampire.


  • While more upbeat and confident than UT Napstablook, he's not as extravagant as UT MTT and his shyness in public is well known.
  • As he likes his arms rather than his legs, he has noodly legs and bulky arms with music controls.
  • When moved to tears by music, he creates a dapper blook hat. His tear trails light up to the beat.
  • His shoelaces are loose and he sometimes trips over them.
  • His box form has a pair of square headphones that become an awful trend in the Underground, making him off his own brand when he gets normal ones built into his EX body.
  • He has longer hair than the original Napstabot.
  • His NEO fight is actually a fight.
  • His Halloween costume is a witch.


  • While more lively than in UT, he still isn't talkative.
  • Rather than purple, he turns your soul orange, making you jitter uncontrollably like you're standing on hot coals.

Nice Cream Guy

  • He's not a creepy jerk, he just has a headache from Club Spook's constant music.
  • Primarily the club's bartender, but he sells frozen treats and milkshakes as well.
  • He also sells ghost sandwiches, but only to ghosts.


  • She has a crush on Sans after the True Pacifist route. She met him because Sans made knock-knock jokes trough Echo Flowers.
  • She's much more reclusive than UT Asgore.
  • Desperately tried to call off the anti-human policy, but couldn't, and now she's trapped in her duty.
  • The first time she killed a human it was not intentional and tried to reason with all of them.
  • She uses a scepter rather than a trident.
  • Is very angry at Asgore.
  • Her scepter flashes rather than her eyes. She destroys the MERCY button with fireballs.
  • Her nickname outside of the AU is Orchid.
  • Her Halloween costume is the queen of Halloween.

Monster Kid



  • She used to be a ghost (not related to the Blooks) living around the river between Snowdin and Waterfall.
  • She accidentally became corporeal after staying in Snowdin when she was sleeping in the snow.
  • She likes drawing in the snow and sitting/leaning on people's heads.
  • She uses snow, ice and fire magic, as well as blue attacks.
  • The fire on her scarf never spreads for some reason.
  • She likes Hotland and warm and spicy food, even though it could kill her.
  • She occasionally breaks the 4th wall by mentioning her art struggles or rambling about character developments.
  • She's more confident, extrovert and fiery than the non-swap Snoey.


Locations are generally the same, aside from small changes matching the characters' placements.

  • The Ruins are filled with flowers rather than dead leaves.
  • The Ruins are still accessible after leaving.
  • Grillby's is replaced by Muffet's.
  • Snowdin has one more sentry station, as Sans manages 3 and Papyrus 2.
  • Alphys' house is dug underground closer to the lava level, and slightly farther away than Undyne's in UT.
  • The Blook Snail Farm is a luxurious snail salon.
  • Water channeling pipes lead to Undyne's lab to keep it cool since she still can't stand the heat.
  • MTT Resort is replaced by Club Spook.
  • Toriel's throne room contains the dead tree and red leaves. The humans are buried below there so there is no coffin room.


  • The relationships between Sans and Undyne and Papyrus and Alphys are much closer than in Undertale.
  • The genocide route is made to be more like classic UT, putting Sans, Papyrus, Undyne and Alphys back in their original positions.
  • The AU also has a canon Outertale version.



  • The AU's name is inspired by Swapfell KH, better known as Swapfell Purple or just Swapfell.
  • The AU was created to fix the parts of Underswap the creator didn't enjoy, like Papyrus' smoking.or Napstaton barely acting like UT Napstablook.
  • Alphys' scarred eye is swapped from regular Underswap to not make her and Undyne's injuries seem too coincidental.
  • While the characters have nicknames, it has no relevance in the AU itself and is just a way Miss Holoska likes to refer to them as.