Undertale AU Headcanons

Headcanons for the UMTV with a focus on Sans AU's.

[charafansmile]

Quick how old do you think chara was when they died

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15+

dawg Idk they just spawned in

Voting ended onApr 5, 2025

[fuckyeah-hetalia]

Here's the blorbo one.

[umtv-headcanons]

Dream: People just need a little light in their life!

Swap: Dream, you can't set people you don't like on fire...

Dream: ...They just need a little spark of happiness...

[chronicfandombrain]

Uh so I made a character bingo if anyone wants to try it (:

[glitchysquidd-deactivated202408]

Give me Characters >:)

[dreemurr-skelememer]

noooo okay but ink would listen to error talk about undernovela for as long as he wanted

[dreemurr-skelememer]

they're the only two people in the multiverse who like AUs in that same exact way and they're the only ones who talk about AUs like they're stories.

they get each other. they're thick as thieves even if their values are a bit insane.

[dreemurr-skelememer]

they also both have AUs they want to keep around no matter what.

error has outertale, and ink has the zephyrtop au

obvs error is more destructive and cares far less about the AUs than ink is but they have so many similarities and things to bond over and both of their unending loneliness deserves each other's company

[chronicfandombrain]

Uh so I made a character bingo if anyone wants to try it (:

[umtv-headcanons]

Consider:

NM’s goop-stuff freezes when its too cold.

Do as you wish with this. :)

I find this a hilarious thing to think about two reasons.

1. In my mind, negativity=cold. So NM runs a little cooler

2. Because of this, he can use ice magic (no, idk why my brain thinks that)

But, no yeah, it makes sense that his goop/liquid negativity (or hate?) would be able to freeze

....This gives the question, does it melt off if he's in a really hot place?

[umtv-headcanons]

Do you have any head-canons for Cross & Lavender from NatureTale?

I don't know anything about NatureTale, so nothing for Lavender. Sorry!

But, Cross! Yess..

Sexuality Headcanon: Bisexual (cannon, but, eh)

Gender Headcanon: Non-binary, but masc. leaning. (He/him | they/them | xe/xem)

Height! 5ft 7in (170.18cm)

I think that due to the deafening silence from essentially a copy of the Anti-Void they don't really care for all blank spaces

Also, tying into that. You can't tell me that X-Gaster let xem (or his Papyrus!) have a lot of knick-knacks. So of course, they now have a collection. Of just. Things. Like a crow. Shinies.

Yeah, that's all I can think of right now.

[givemeangstymemes]

Reblog if your inbox is ALWAYS open for random asks, even if you haven’t reblogged any meme

[paintpanic]

Send me a character and I’ll give you some of my thoughts on them!

[umtv-headcanons]

Appearance Headcanons: Height

Classic- 5ft

Ink- 4ft 11in

Error- 5ft 8in

Reaper/Death- 5ft 7in

Nightmare- 5ft 5in

Dream- 5ft 4in

Swap/Blue- 5ft 4in

Killer- 5ft 4in

Horror/Axe- 5ft 11in

Dust/Murder- 5ft 5in

Cross- 5ft 7in

Lust/Hearts- 5ft 3in

Outer- 4ft 10in

Ccino- 5ft

Geno- 5ft

Fresh- 6ft

Epic- 5ft 8in

[umtv-headcanons]

I'm going to update this in a bit, might add more Sanses, but mostly to update my heacanons (? idk how to spell)

[umtv-headcanons]

For headcanons how about Dust?

Dust/Murder (Dusttale)

Sexuality Headcanon: Demi…demi-romantic, specifically

Gender Headcanon: Man, he/they, like if you were to order the gender, “male” from wish, it’s male, yes, but slightly off.

A ship I have with said character: Horror/Dust, there’s more but that’s the current obsession.

A BROTP I have with said character: Killer and Dust, they get very chaotic.

A NOTP I have with said character: Him and G!Sans

A random headcanon: While he does see his Paps, he also sees the others of his AU, but they’re less distive figures. So when his Paps he can see full color head, neck/scarf, and gloves the others are shadowy shapes with white eyes, but he can tell who they are, as well as hear all of them. So schizophrenia.

General Opinion over said character: Eh, reasoning for dusting his AU makes sense. On a scale of 1-10…7.5/10 likable.

[umtv-headcanons]

Classic (Undertale Sans)

Sexuality Headcanon: Bi-romantic Gender Headcanon: Male (He/Him/His) A ship I have with said character: Grillby x Sans A BROTP I have with said character: Toriel and Sans A NOTP I have with said character: Gaster x Sans, no thanks! A random headcanon: He likes rubix cubes. IDK, man, they're neat. General Opinion over said character: Pretty chill, laid back. I, too, like ketchup a bit more than is probably healthy.

[demrpmemesandinboxstuff-blog1]

SEND ME A CHARACTER AND I’LL DO THIS;

Sexuality Headcanon: Gender Headcanon: A ship I have with said character: A BROTP I have with said character: A NOTP I have with said character: A random headcanon: General Opinion over said character:

[umtv-headcanons]

Nightmare: I am Nightmare, Crusher of Dreams!

Killer: Dream quivers before him!

NM @Dream: Fuck off!!

[umtv-headcanons]

Appearance Headcanons: Height

Classic- 5ft

Ink- 4ft 11in

Error- 5ft 8in

Reaper/Death- 5ft 7in

Nightmare- 5ft 5in

Dream- 5ft 4in

Swap/Blue- 5ft 4in

Killer- 5ft 4in

Horror/Axe- 5ft 11in

Dust/Murder- 5ft 5in

Cross- 5ft 7in

Lust/Hearts- 5ft 3in

Outer- 4ft 10in

Ccino- 5ft

Geno- 5ft

Fresh- 6ft

Epic- 5ft 8in