What Themes Are Common In Sans Dream Fanfiction Plots?

Okay, so with Sans pairings in 'Undertale' dream sequences, I notice a huge split between fluffy comfort and heavy existential dread. A lot of fics use the dreamscape as a safe space to explore a relationship without the baggage of timelines or his canon apathy—like Reader or Frisk just hanging out at Grillby's, sharing puns, that sort of low-stakes sweetness. But the more interesting ones dig into the meta-angle. Sans is aware he's in a game, right? So dream romances often become about vulnerability in a constructed reality. He might confess feelings he'd never admit awake, or the dream itself starts glitching, turning sweet moments into horror. I've seen fics where the other character realizes they're in Sans's dream, not their own, which flips the whole power dynamic. Common thread? Intimacy built on shared secrets or hidden pain, way more than physical stuff. The skeleton thing almost becomes irrelevant, it's all about two minds meeting in a headspace nobody else can access.

I’ve been scrolling through the Undertale tag for years now, and I’ve got to say, Sans/Papyrus stuff can be a real mixed bag. It’s definitely a more niche ship compared to the big ones like Sans/Reader or Sans/Undyne, and that almost seems to shape the themes people go for. A lot of it leans into the whole ‘brothers who have only ever had each other’ dynamic, but pushed to an extreme. You get these isolated, post-pacifist run AUs where the surface never happened, or where something went terribly wrong and they’re the only two left in the Underground. The stories often focus on dependency—how their codependency curdles into something possessive and desperate when there’s literally no one else. It’s less about romance in a traditional sense and more about exploring the cracks in their seemingly unshakeable bond when it’s all they have. Another huge theme is guilt and atonement, usually from Sans’s side. Writers love digging into his secretive nature and the implied ‘scientist’ backstory from the game. Plots where Papyrus finds out something Sans did in a previous timeline, or experiments he was involved in, and the fallout from that. The ship then becomes a vehicle for Sans seeking forgiveness, or Papyrus trying to understand the weight his brother carries, which inevitably blurs lines. It’s angst with a capital A, often pretty heavy on the psychological drama. You don’t see a lot of fluffy coffee-shop AUs here; the tone tends to be gritty, introspective, and claustrophobic, which honestly fits the characters when you twist them that way. I’ve even seen some that blend in horror elements, playing with Sans’s powers and Papyrus’s innocent trust in really unsettling ways. What surprises me is how rarely it’s played for pure smut. When it gets physical, it’s usually tangled up with these psychological themes—a manifestation of control, comfort, or shared despair. It’s not my personal cup of tea, but I respect how the writers committing to this ship are usually trying to dissect something specific about their relationship, for better or worse. It feels like a ship built more on character study than wish-fulfillment, which is kinda fascinating in its own dark little corner of the fandom.

Man, that's such a specific ask but I love it. The emotional possibilities with a Sans who doesn't dream—or can't, or won't—are actually huge if you move past the surface-level angst. One plot I keep coming back to is Sans discovering he lost the ability to dream not from some grand trauma, but from simple, relentless burnout. The story isn't about regaining it; it's about him watching Papyrus build elaborate pillow forts to catch 'good dream butterflies' for him, and realizing his emotional depth isn't measured in REM cycles. The best versions have him finding new ways to connect that feel grounded, not magical. Another angle I've seen done well ties into his scientific side. What if the 'dreamlessness' is a side effect of his own tampering with timelines? He chose stability over the chaotic, beautiful mess of dreaming. The emotional core becomes about the cost of being the reliable one, the anchor. The payoff isn't a restored ability, but a quiet moment where he finds a strange, waking beauty in something Papyrus does—like decorating the house with absurdly colored lights—that fills the same imaginative space a dream would. That feels more real to me than yet another magic-solution fic.

Honestly? After scrolling through way too many of these, most start feeling like the same three flavors reheated. You've got the fluff where Sans finally lets his guard down and they just eat noodles and watch stars, which can be sweet but sometimes lacks conflict. Then there's the darker, post-genocide route stuff where he's grappling with his failure and Frisk's determination becomes a point of tension or healing—those can get pretty intense. A weirdly specific one I keep seeing is 'pacifist-run aftermath' where Sans knows Frisk reset and is deeply, existentially messed up by it, leading to either angsty hurt/comfort or a bizarrely protective dynamic. The 'time loop trauma bonding' theme is basically a subgenre at this point. Also, 'skeleton having a body' is a whole thing. Like, how does that even work? Some writers go full monster biology headcanon, others just ignore it. It's a minor detail but it always pulls me out for a second when they describe him holding hands or whatever. I tend to skim past the coffee shop AUs.

Romantic dream/nightmare stuff tends to fixate on the healing power of affection, which honestly can get a bit repetitive. So many fics frame Dream as this pure, wounded soul that Nightmare's corrupting influence can somehow 'fix' through love. I'm more drawn to interpretations where the romance isn't a cure, but a complication. The best one I read recently had Nightmare deliberately using a fabricated 'dream' of their past harmony to manipulate Dream, who was fully aware of the deception but played along out of loneliness. It was less about salvation and more about two powerful, broken beings choosing a toxic mutual understanding because it was preferable to the void of their actual existence. That moral ambiguity sticks with you longer than another 'love conquers all' fluff piece. A common shorthand I see is having them share dreams or memories, literally visiting each other's 'realms' in their sleep. It's a convenient plot device to force intimacy, but when done well it can highlight how their core concepts aren't opposites but two sides of the same coin. The fear in a nightmare can feel just as intense and intimate as the comfort of a sweet dream, and fics that lean into that shared intensity of feeling—rather than just pitting 'light vs dark'—often feel more genuine.

Honestly, the Sans Dream trope is such a creative sandbox. There's this constant push-pull between Sans's lazy, pun-loving surface and the immense, often frightening power simmering underneath. A standout storyline explores him as the 'Guardian of the Multiverse,' a role forced on him by his own scientific meddling with timelines and his brother's death. Stories built on this see him endlessly patrolling alternate universes, a weary cosmic sentinel who's seen every tragic variation of his friends. The real draw here isn't the power fantasy, but the profound loneliness and dark humor that comes with it. He might drop a joke while preventing a timeline collapse, making the moment feel bittersweet rather than triumphant. Another angle I find captivating is the 'Dream as a Separate Entity' concept. Here, the Dream isn't just a power-up for Sans; it's an ancient, sentient force, maybe even the remnant of a lost universe, that's chosen him as a vessel. This creates fantastic internal conflict. Is Sans in control, or is he being slowly overwritten? Writers get to play with body horror, moments of lost time, and the horror on other characters' faces when they see 'Sans' acting utterly alien. It turns the story into a psychological survival tale for Sans himself. Then you have the more intimate, character-driven takes. 'Papyrus's Keeper' is a heartbreakingly sweet variant. Instead of multiversal stakes, the Dream's power manifests purely to protect Papyrus, triggered only by a direct threat to his brother. It flips Sans's laziest traits into a facade; his 'naps' are actually him scanning timelines for danger, and his casual attitude is a carefully maintained act to keep Papyrus happy and unaware. The emotional core is that quiet, desperate love, and the climax is less about a big fight and more about Papyrus realizing the depth of his brother's silent vigil. I stumbled on one where the big reveal was just Papyrus finding a closet full of broken 'Doge' arm blasters Sans had used to secretly eliminate threats, and it was somehow more powerful than any laser blast. That kind of specific, grounded detail makes the trope feel fresh and personal.

This is a really niche corner of the Undertale fandom, but the core of most Underswap Sans fiction tends to revolve around identity swaps of the skeleton brothers themselves. You've got Sans, who now has Papyrus's energetic, justice-loving persona, but he's still saddled with the immense power and sometimes the latent guilt of his original timeline. A lot of plots mine conflict from that dissonance—this Sans tries to be upbeat and heroic, but the weight of his 'original' memories or his magic being fundamentally different creates a constant internal struggle. I've read a few where he grapples with feeling like a fraud because he's acting a part, or where his attempts to be 'the cool one' spectacularly backfire because he can't shake his more detached, analytical nature. External conflicts often mirror that. Since Papyrus is the lazy, pun-loving one in this AU, you get a dynamic where Sans is desperately trying to keep everything together and protect a brother who might be more cunning or secretly powerful than he lets on. It flips the caretaker role on its head. You'll also see a lot of fics exploring his relationship with an Underswap Alphys, where he might be her overenthusiastic royal guard counterpart instead of a laid-back friend, which creates a whole new kind of lab-based tension. The tropes aren't wildly different from other AUs, but the flavor is distinct because it's about performance versus essence.

Undertale fanfiction focusing on Sans AUs has pretty clear lanes. The ‘fell’ variants dominate—anything where Sans is a more hardened, often cruel version of himself, like in ‘Underfell’ or ‘Dusttale’. Readers love the moral conflict of seeing a character usually defined by lazy humor and secret compassion turn into someone ruthless. It’s a power fantasy with emotional stakes. On the flip side, the ‘swap’ and ‘caretaker’ themes are huge. Think ‘Swap’ AU where Sans takes Papyrus’s more naive and heroic role, or stories where he’s forced into a protective, almost parental role for Frisk or a human. This lets writers explore his softer side under pressure, which hits different when you know his canon cynicism. Crossover fusion fics also pop up a lot. Sans gets dropped into other universes—‘Harry Potter’, ‘My Hero Academia’, even ‘Marvel’—because his sarcasm and OP abilities (Gaster Blasters, teleportation) create instant friction and humor. They’re less about deep lore and more about the fun of watching him outsmart a completely new setting. A smaller but passionate niche revolves around ‘Gaster-centric’ or ‘backstory’ AUs. These dig into his possible creation by W.D. Gaster, experiments, or a past as the Royal Scientist. They’re often slower, angstier, and attract readers who want mystery and tragedy over action. The sheer volume means you can find almost anything, but the core appeal is always twisting Sans’s two defining traits: his laid-back front and his hidden, weary depth. Whether you amp up the edge or strip it away for vulnerability, that’s where the stories cluster.

Reading those stories feels like finding the last packet of instant noodles when you're starving at 2 a.m.—weirdly comforting in a way you can't explain to normal people. It's rarely just about romance; a huge chunk of them revolve around rivalry. I mean, obviously, but they take the competitive 'who can build a better farm' vibe from the streams and crank it into this tense, high-stakes dance. They're constantly trying to one-up each other, but there's this undercurrent of mutual, grudging respect that borders on obsession. You can't look away from the other person. That obsession often twists into something softer, though. A lot of writers use the 'rivals to lovers' blueprint, but the emotional core is usually a shared, profound loneliness. They're both at the top, isolated by their fame or skill, and the only person who truly gets the pressure is the one they're supposed to be beating. So you get these scenes of quiet understanding after a long stream, or secret meetings where they don't have to perform. The emotional payoff isn't grand gestures; it's Dream letting Sapnap see him without the mask, or Sapnap admitting he's scared of being left behind. The vulnerability feels earned because it's built on that foundation of fierce competition. There's also a surprising amount of angst around change and growing apart. Fanfiction often picks up on the real-life narrative of friends growing up and their dynamics shifting. Stories will explore the fear that success or new relationships will break their bond, turning that anxiety into narratives about clinging to something precious as the world tries to pull it away. The emotional tension comes from wanting to preserve a golden era while knowing nothing stays the same, which gives even the fluffiest fic a melancholic edge.

They don't exactly share a universe, do they? It's a crossover that shouldn't work, but somehow it does. The common thread I keep seeing is a shared obsession with hope, but from two completely cracked mirrors. Sans judges you over and over, a jaded observer who's seen the worst outcomes. Nagito manufactures despair to fuel his twisted version of hope, believing in a grand narrative. Fics often turn this into a battle of philosophies, with Sans's lazy pessimism clashing against Nagito's frenetic, self-destructive optimism. What really gets me are the ones where Nagito's luck cycle becomes a meta-narrative tool. Sans, with his time-loop awareness from 'Undertale' resets, might recognize a pattern he can't break. The emotion isn't just angst; it's a profound, cosmic loneliness. They're both aware of larger systems—game mechanics, storytelling tropes—and are trapped by them. The best stories I've found use that to create a weird companionship, two broken people who are the only ones who can see the cracks in their own realities. It's less about romance and more about two different kinds of madness understanding each other. The tone leans heavily into existential dread, but there's always this undercurrent of black comedy. Sans's deadpan delivery against Nagito's unhinged monologues writes itself, really.