This article, Mersmis Alxyga, is owned by HolyTraitor. Please do not edit this article without their explicit permission.

The Goat-Fish

Mersmis is a strange-looking monster that can be found inside the Ruins and the Capital. He is Shyren's only friend, as well as Aaron's companion. He tends to make music to play in Shyren's band.

Mersmis can be found in Home, standing between two fences, with four graves behind him and a path leading towards his house in between two tall towers. A copy of this can be found in New Home, which is identical, except that there are no graves and the place is completely empty.



Mersmis appears to be a Capricorn-like creature with a long, scaly, thick, blue tail and a white goat head with strange forward-facing horns, black eyes and large, floppy ears.

His chest is blocked by the chain-mail shirt and steel shoulder-pads he wears during his fight. However, while he's not fighting, he wears a large, green sweater that says "FillerForever".


Mersmis is a usually calm person, tending to his family's grave and eating chili. He's an extrovert, making friends with almost everyone except Jerry. 'Cause fuck Jerry.

However, he goes crazy when outsiders trespass his territory or when his chili disappears. His neighbors call him a "mood-swinging goat man", and that they love him for it.


A recording of Mersmis' voice.


Mersmis can create an array of stars encased in bubbles that cover the top and edges of the Bullet Board. After swooping across the Bullet Board, they come back, fuse into a single, giant bubble which implodes on itself.

Another one of his attacks is one that he rarely does, which he uses his tail and sweeps the Bullet Board.

He also can use fireballs and stars, which may form into constellations and shoot other stars. Not only that, he also uses a few attacks from monsters like Aaron, Woshua and other Waterfall monsters. Sometimes, he mixes the attacks together.

His special attack is just a cluster of stars, formed to look like the Milky Way galaxy. The black hole in the middle tries to suck in the SOUL, before imploding on itself.

Soul Mode

Mersmis can change your heart mode into "Monster Soul" mode. During his attacks there are instead two heart boxes, one containing your red heart and one containing an upside down white heart that constantly moves inverse to you - if you head up, it heads down, etc.

Each box is filled with white and gray projectiles. The white ones damage you like normal, but the gray ones don't affect you. Inversely, the white heart is unaffected by the white projectiles, but getting hit by the gray ones damages Mersmis.

The fight can include other modes, such as blue, green, and yellow, but the concept remains the same - the white heart's movements are opposite yours.


Health Points: 119

Attack: 8

Defense: 2

Execution Points on Kill: 15

Gold on Win: 10

Actions: Ask Nicely, Persuade, Threaten, Glare, Offer Chili*

*Only available if the player is carrying any chili


True Pacifist Ending Credits

  • White Text - "Still Underground With His Family"
  • Yellow Text - "Happily Living His Life On The Surface"
    • To achieve Yellow Text, one must offer Mersmis chili after asking nicely three times, and yet before persuading him. That will lead to his sprite smiling in the end credits, instead of his usual, calm expression.



Needleteeth, Toriel, Froggit, Whimsun, Migosp, Moldsmal, Loox, Whimsalot, Astigmatism




Migospel, Parsnik, Moldessa, Filler Froggit


Unnamed Father, Unnamed Mother, Unnamed Sister, Unnamed Uncle


All you have to do is ask nicely three times, optionally glare at him once and then persuade him five times. You can also offer him some chili, which can be found in a box next to his house. Afterwards, he can be spared.


  • "I was born here, and I will die here." [Neutral]
  • "I will not abandon this land! Not now, not ever!" [Neutral]
  • "Leave me to my birthplace! [Neutral]
  • "This place is sacred! Away with you!" [Neutral]
  • "No. Leave me alone." [Ask Nicely #1]
  • "No! Go away"! [Ask Nicely #2]
  • "NO!! STOP BOTHERING ME!!" [Ask Nicely #3]
  • "Hah! Nice try, but you won't convince me!" [Persuade #1]
  • "Well, you DO make a persuasive argument... but I still won't leave!" [Persuade #2]
  • "Well, that is true... no matter! I will stay down here!" [Persuade #3]
  • "B-But..." [Persuade #4]
  • "Okay, FINE. I'll leave. But you owe me one." [Persuade #5]
  • "Try me, creep." [Threaten #1]
  • "You're bluffing. You don't scare me." [Threaten #2+]
  • "Please don't look at me like that." [Glare #1]
  • "Don't smile like that. It's creepy." [Glare #2]
  • "Stop. You're creeping me out." [Glare #3]
  • "OH! Thank you so much! Boy, I love these..." [Offer Chili #1]
  • "You got more?! OH MY GOD!" [Offer Chili #2]
  • "Whooaaa! You must love chili like I do!" [Offer Chilli #3]

Flavor Text

  • None of your business. [Check]
  • Mersmis Alxyga blocks your path! [Encounter]
  • Mersmis Alxyga swam close...? [Encounter]
  • Mersmis puffs his chest in an attempt to look intimidating. [Neutral]
  • Mersmis sharpens his horns and prepares to attack. [Neutral]
  • Smells like TMT-Brand Insta-Barricade. [Neutral]
  • Smells like magical powder. [Neutral]
  • Smells like ducks. [Neutral]
  • You ask Mersmis to leave the Underground nicely. He taps his tail impatiently. [Ask Nicely #1+]
  • You have failed to threaten Mersmis. [Threaten #1]
  • You have failed to threaten Mersmis... again. [Threaten #2]
  • Mersmis is feeling REALLY uncomfortable with your glare. [Glare #1-3]
  • Mersmis is too frightened to fight any longer. [Low HP]
  • You iffered Mersmis some Chili. He accepts with joy. [Offer Chili #1]
  • You offered Mersmis more Chili. He happily takes it from your hands. [Offer Chili #2]
  • You offered Mermis a last can of Chili. He seems satisfied. [Offer Chilli #3]
  • Mersmis is prepared to leave. [When spare conditions are met]



  • Mersmis's name is actually an anagram of "Galaxy Swimmer", due to him being a capricorn.
  • The flavour text occasionally seen during his battle (Smells like ducks and Smells like magical powder) is a reference to the wizard in Team Fortress 2, Merasmus, due to their names being similar.
  • A quote directly from Mersmis, "No. Leave me alone", is a reference to Schmoyoho's song, "DJ Play My Song Now (No, Leave Me Alone)"
  • Mersmis belongs to HolyWyvern, who created the first ever Original Character in the Undertale Roleplay Wiki.
  • Mersmis is blinded by addiction to ancestry, and thus, his Lost Soul can be fought in the end of the True Pacifist route.
  • Mersmis was inspired by the old porcupine in Ice Age: The Meltdown, where he refuses to leave his hole, saying that he was born in it, so he will die in it.

Other credits

Thank you, SquidFairy, for helping me with the page layout!

Thank you, LennyFacedCupcake, for Mersmis' sprite!

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