Undertale Headcannons

A Page for posting all of your headcannons for the video game, Undertale

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The Underground's roof is made of a strange black stone. It also has magic gems that look like stars on it. The gems are the source of the barrier, but are also the things that keep the mountain from falling in on them and crushing them all, because... giant cavern and all.
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12 days ago
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Gaster is Sans's and Papyrus's dad, but not in the way y'all think. He created Sans in a science experiment trying to grow a human soul
proud of his work, he repeated the procedure with slightly different measurements and formulas and got Pappy.
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22 days ago
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The fire elementals (Grillby and Fuku) can have their flames change in brightness/dimness

When they are sad, or something is wrong their flames get dim
When they are happy, or flustered, their flames get brighter
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on June 30
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I think Chara might have a case of severe childhood schizophrenia, considering the way they talk at some points and several hints throughout the game that they could have a mental disorder.
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on June 29
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Grillby drinks Hot Sauce the way Sans drinks ketchup
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on June 11
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uploaded a photo
Hadcannon Robot Napstablook
Undertale Headcannons's Photo 0
on May 15
[Undertale] Tem get cool leg (Comic Dub)
[Undertale] Tem get cool leg (Comic Dub)
All voices in this comic belong to me. Original comic: http://binaryowl.tumblr.com/post/133114887410 Tem village song: https://www.youtube.com/watch?v=Jqeqp-...
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on April 16
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My headcannon Mettaton voice is Jeffree Star
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obsessions
oH MY GOD YES
on April 17
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on April 16
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Underswap Grillby, instead of having Spiders, he has Flambos (The fire cat things from Adventure Time)

http://images5.fanpop.com/image/photos/29100000/So-THATS-Where-I-Came-From-adventure-time-with-finn-and-jake-29107241-480-320.png
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on March 07
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Undyne was the one to defeat the human with the green SOUL. That human was a cook and a very kind person to her, so she decided to honor them with an attack and by learning how to cook.
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on February 19
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Sans's mailbox is filled with concerned mail from Grillby. Also reminders to pay his tab.
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on February 18
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Sans and Papyrus both get flustered and blush easily.
So the gay robot operator and fireman take advantage of it.
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on February 12
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That somewhere, in another universe, the world is a musical, and either Flowey/Asriel or Chara sings this song to Asgore. And it sounds like this.
https://www.youtube.com/watch?v=_rMqY_J1Jbg
Paramore: Ignorance [NateWantsToBattle Music Song Cover]
Paramore: Ignorance [NateWantsToBattle Music Song Cover]
A music cover song of Paramore's "Ignorance" by Nathan Sharp (NateWantstoBattle) iTunes ► http://j.mp/ignoranceonitunes Amazon ► http://j.mp/ignoranceonamazo...
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on February 11
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That this is how it went down:
https://www.youtube.com/watch?v=wSTcRzpL7pQ
Death by Glamour (UNDERTALE ANIMATIC ) - Mettaton vs. Frisk Fight
Death by Glamour (UNDERTALE ANIMATIC ) - Mettaton vs. Frisk Fight
WHO’S THE REAL STAR HERE?! AND WHO WILL BE OUTSHINED?! --------- ALSO CURSE THOSE TYPOS!!!! No matter how many times you go over your video, they always mana...
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WastingMyLifeOnline
I've watched this, like, a million times o3o
on April 16
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UnderSquad
it seems i cried during the for the fans part.
...
so i'm not made of stone.
on February 11
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Kanya888
It's so peautiful and cute just
on February 11
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AnimatronicHeart
Yes!
on February 11
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Duns_For_Hands
I love this :00
on February 11
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on February 11
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That this is Undyne's voice (qpoilers for no mercy route):
https://www.youtube.com/watch?v=_Vkl8BWVg2U
The Undying // Undertale Comic Dub
The Undying // Undertale Comic Dub
*Undertale Genocide Run Spoiler Alert* *Also Minor Bad Language* Comic by the3Ss: http://the3ss.deviantart.com/ Original comic: http://the3ss.deviantart.com/...
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on February 11
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Head cannon Ages

Frisk - 9
Chara - 10
Asriel - 8
Toriel - 38
Asgore - 43
Sans - 25 See More▼
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on February 10
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muffet is the boss of a secret clothes black market and mettaton buys everything she makes, but doesn't know it's hers
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on February 09
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Gaster loves kittens and all cute things.
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on February 09
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Frisk climbed the mountain because they wanted monsters and humans to be friends again. Upon hearing the story at a young age, they decided to mend the relationship between the races.

Mettaton wants to take care of a young person and teach that young person his ways, as an apprintice.

Undyne's parents wanted her to be a nice and gentle lady, which is the reason she knows how to play piano and why she has such a nice house. But, she was a rebel with some anger issues, so the See More▼
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on February 09
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Muffet is well acquainted with Mettaton and Alphys. They aren't bestest of friends, but Mettaton and Alphys stop by to see her once in a while.
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on February 09
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