1 - 20 of 44 Works in Determination Experiments (Undertale)
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Summary
A series of dialogue. A set of numbers.
After a slew of countless RESETs, Flowey is driven out of sheer desperation to commit a taboo he has never tried before.
While Papyrus vows to try to help and understand his friend…the truth comes to light when Flowey expresses that he will never feel the same way any other monster can.
Flowey comes up with his own solution for this, and it's not a pleasant one. But apparently that's okay since consequences are usually beyond Flowey.
…But now things are suddenly escalating beyond his control. Not that Papyrus ever had any control to begin with.
Flowey, the Human…is who is in control really the point?
…So then…what's left?
Only the Pretty Poppy can decide now.
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waking up in the body of a skeleton wasn't exactly what you were expecting. the last thing you remember was... the Only thing you remember was a deep, freezing cold (like you would never be warm again), disorienting, blinding, swirling white, and a flash of burning pain. then... nothing. nothing about who you are, who you were. though... the two skeletons in front of you seem familiar, like a memory you can't quite reach. here's hoping you can figure out Something.
the first one falls
Series
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I'LL PAINT THE KITCHEN NEON, I'LL BRIGHTEN UP THE SKY. by Sneakyfox55
Fandoms: Undertale (Video Game)
28 Aug 2025
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Sans gets sick.
Series
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Frisk fought with omega Flouwe, like it should happen, then suddenly the an error occurred and Flowey stol Frisk's reset and part of his soul. Now Flowey has the chance to kill frisk onec and for all, but flowey has other plans.
- Language:
- English
- Words:
- 594
- Chapters:
- 1/1
- Kudos:
- 4
- Hits:
- 55
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Summary
His other hand activated the recorder. The red light blinked to life, casting faint illumination on the darkened lab. Everything around him was a monument to forgotten science: faded monitors, humming generators, glyph-covered machinery that hummed in a language only he still understood. He leaned in, eyes glowing dimly behind his cracked skull. “You’re not going to like this,” he said, not without sympathy. “But then, progress rarely asks for permission.”
***
Day nine: June of Doom- Gaster experiments on a human child.
Series
- Part 9 of June Of Doom 2025
- Language:
- English
- Words:
- 335
- Chapters:
- 1/1
- Kudos:
- 2
- Hits:
- 75
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Summary
The world choked on war, but for Chara, Kager’s attack was the true devastation. Raiden, her love, didn't just die; his Lumina—his very essence, memories, him—was shattered. Gone. In that void, something cold and sharp awakened within Chara.
Determination. For her, it's not hope; it's power. A RESET. Her one chance to fix this goddamn mess, even if it means tearing reality apart. Love is the raw, constant ache. But HATE, a dark, intoxicating power she's now embracing, will be the edge of her knife. Kager will pay. Raiden will be made whole.
This path is blood and betrayal. She’ll navigate a world of deceit, facing enemies in guises she should trust—even a twisted version of her own damn face from a timeline drowned in LV. Expect gritty magic, brutal fights where survival is the only rule, and the unsettling feeling that any memory could be a breaking point. Or forge her into something worse.
This is Chara's war. Her burden. Her one fractured hope.
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After defeating Asriel in battle for what felt like the thousandth time, something new finally happens. Instead of disappearing, a new magic consumes the human souls and gives them life once again. With the barrier broken, they'll be able to go home and get their own happy endings, right? Unfortunately their families were disturbed by the way they came back to life, and because of the time gaps some felt too old to be parents again.
So where do they go? With the monsters that killed them, to "make amends."
Series
- Part 2 of Surface Souls AU
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There's been an epidemic of monsters suddenly falling unconscious, never to wake up. It's been labeled as falling down and the patients the fallen. As the Royal Scientist, Alphys has been put in charge of fixing things. But what is she supposed to do when her girlfriend's mom is among the fallen? Or when she makes things so much worse? How can she face Undyne or tell her what she's done? How will she fix this?
Might be a little out of character because I haven't played true pacifist in a while and I'm at the Sans fight so I don't want to reset to start true pacifist
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After the fall of the Barrier, life on the surface has begun to settle—but not all wounds heal with freedom. Frisk and the monsters navigate the quiet rhythms of a new world while remnants of the Underground’s past ripple beneath their feet. Between sleepless nights and strange seismic readings, old instincts stir, and a journey begins—one that may unearth more than just stone.
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After everything went to black, Clover asked themselfs if this was how death was. If they had anyone to wonder.
It was too dark to see, too silent to hear, too empty to even think about it. A little more and they could feel the cold, hard glass of the container they're inside, trapped for who knows how long. It could be hours, it could be days, or it could be centuries.
It feels like centuries, until it doesn't.
And a dark, misterious ceiling with a light too bright welcomes them. It's not a warm welcome.
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[ It's around seven years since the sixth human fell into the underground. With six human souls captured but no luck in obtaining a seventh, the monsters in the lab decide to start on a new project. ]
OPERATION NEW SOUL
The plan to create a human soul.What if they combined a monster soul with a human one. It seemed silly really, but what could they say, no? So they tried it, They gather fragments of the previous human souls and infuse them with determination.
With half of a monster soul, and half of a human soul—they made…well, a soul. A stable one, maybe? No one really knew.
Some urge immediate use, fearing it will wither like the others. But the lead scientist insisted, “We must wait until its determination is strong enough to break the barrier.”
It seemed foolish. How could a soul, cobbled together in a lab, be strong enough?
Until you’ve opened your eyes.
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“i’m doctor w-” he cut himself off, reaching up to grab at his jaw. That wasn’t how he spoke. That had never been how he spoke, not in all his years of life. His hands did the speaking where his mouth did not, and it had been that far too long for him to recall whether he couldn’t or merely didn’t. With the sick feeling of magic rising in his trachea, he attempted to sign, hands trembling nearly too hard to form words.
~
Sans and Papyrus are two halves of a forgotten whole. Sans refuses to let that lost SOUL go.
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RS! Undertale & Deltarune Information and fics by Anonymous
Fandoms: Undertale (Video Game), Deltarune (Video Game)
15 Nov 2024
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Basic character and world information, this is official information. If you wish to find out more information about the AU there is a Tumblr blog for it
Series
- Part 3 of Aw shit my UT phase is back
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A particle physicist working in Ebott City is pulled into a project tasked with unravelling centuries of research to bridge the gap between human and monster science. As she delves deeper, she becomes entangled with an enigmatic entity that hides the desired explanations from her.
Driven by an insatiable need for answers, she fixates on one goal: to rip this 'man who speaks in hands' from the abyss, no matter the cost.
(Sorry!! I’m bad at writing summaries)
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Summary
Chara and Asriel record their adventures in the Underground with an old portable tape recorder and a cassette video recorder with a cracked screen.
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Within Darkness, There is Always Light by orphan_account
Fandoms: Undertale (Video Game)
21 Sep 2024
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Summary
Frisk wakes up in a strange place with no memories, only barely being able to remember their name. As they begin to explore their new surroundings, a rude spirit insists on pestering them. Soon they realize the reality of the situation they're in. A neglectful and fearful world.
They're stuck with the consequences of a past they had no memory of. A painful sense of guilt follows wherever they go.
Will they save those they come across?
Or will they be the one who is saved?
Or will the creatures in the cave walls find them first?
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Scientist W.D. Gaster is ordered to save the life of a kid, and when he figures out how, it determines the future of his experiments, the Underground, and his legacy.
- Language:
- English
- Words:
- 2,715
- Chapters:
- 1/1
- Kudos:
- 5
- Hits:
- 134
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Summary
When I walk
down the street,
I feel the grit
between my teeth.I think I care?
I think I care.
I don't care,
I fucking swear.Bite my lip
to stop the laughter,
nobody better
no ego bigger. -
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Summary
Prehaps, Doctor W.D Gaster was doomed right from the very beginning, maybe nothing could have prevented the inevitable.
The full story of Doctor W.D Gaster, Sans, and Papyrus; right from when Gaster was a little kid before the war, up until even after the barrier breaks, freeing monster kind. (This is also based on Handplates by Zarla, so be sure to check that out!)This story does contain heavy topics.
FYI: More tags, and characters will be added as the story progresses. I will also work out an update schedule. -
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Summary
This isn't just about the humans, anymore. You won't die. Flowey's killed you, over and over, and you're going to overpower him this time. You have a reason.