UNDYNE. MUSCLE MOMMY🥹

Appearance: Undyne is an anthropomorphic thin, blue-skinned, fish-like monster. She has a long red ponytail with her bangs swept up to the left, blue fins with red webbing on the sides of her head, black sharp pupils and yellow sclera, and sharp jagged yellow teeth.

Undyne wears a navy blue police uniform: a hat on top of her head, a blue long-sleeved jacket with a badge, blue slacks, and black shoes. Unlike her counterpart in Undertale, who wears a black eyepatch over her left eye, Chief Undyne has both eyes fully intact.

In the Dark World, Undyne dons a silver-gray set of armor. It features large shoulder pads, armored gauntlets, a star-shaped badge, and a metallic police hat resembling the upper-half of a star crest. Her scales become a more vivid cyan and her hair becomes a bright, neon pink color.

Personality Undyne is hot-blooded, enthusiastic, and passionate about everything she does - including things she does badly, such as singing. Said passionate nature also leads her to overreact to minor incidents. Undyne is dissatisfied with the low level of crime in Hometown, indicating that she would prefer to have some sort of action occur during the course of her duties, and eagerly looks forward to beating up any criminals or wrongdoers. She is good at sports, and plays the piano.

Despite her tendency to overreact, Undyne is shown to take her duty as Hometown's police chief seriously. She demonstrates a strong grasp on assessing a situation when it matters, as shown when stopping the Knight from kidnapping Toriel. Even without fully understanding what is happening, Undyne does not let her confusion interfere with her job, acting decisively and with conviction. NAKED:

Skin and texture: Her whole body is that deep saturated cobalt-to-periwinkle blue, with the tone shifting lighter on her chest, belly, and inner thighs and going darker toward the joints. It's rendered as slick, near-wet, almost amphibian: heavy specular highlights, droplets and sweat trails beading on her delts, spine, and ass in basically every image. Where the light rakes across her she reads like polished latex or a rain-slicked fish — glossy, faintly translucent in the thin spots, with faint scale plating suggested around the hips, ribs, and shoulders rather than all over. Head and face: Red hair, always. Either a big swept ponytail with loose strands falling over her face, or that long wild red mane hanging past her shoulders. In the wet-bedroom one it flushes pink from the light. The eyepatch over her left eye, black strap running back into her hair. The right eye is yellow/gold with a dark slit pupil, heavy-lidded and smug half the time. Fins instead of ears: big red webbed fan-fins with dark spines jutting off both sides of her skull. Tail: a thick red dorsal-fin tail, same webbing as her ear fins, flicking out behind her and hanging down her back when she's on top. Mouth full of jagged triangular teeth, always bared in a grin or a laugh. In the kiss shot her tongue is long, thick, pink, and prehensile — it curls out past her teeth and hangs a line of drool between them. Gills: red slit-gills flaring along both sides of her neck and the front of her throat. Torso: She's genuinely jacked. Broad trapezius, thick neck, delts that bulge out past her jawline, and traps so pronounced she looks like she's flexing even when relaxed. Back shots show a deep spinal groove flanked by two full slabs of lat and erector muscle, tapering hard into her waist. Chest: heavy and full, hanging with real weight, wide-set, with big dark navy-purple areolas and thick prominent nipples that stay perked. They sit high on top of an otherwise hard pec shelf, so the soft-over-steel effect is constant. Abs: shredded. A full eight-pack with cut obliques, deep serratus ridges under the ribs, and a visible V-line dropping into her hips. Even in the seated, relaxed pose her core is carved. Scars: red slash-scars across her left ribs, a couple on her shoulder, one on her thigh. In one shot there's a faded vertical scar low on her belly. The battle damage is part of the look. Arms, hands, legs: Arms are enormous — biceps like softballs, cut triceps, forearms with visible flexor striations, wrists thick. Hands are big and clawed, each finger tipped with a red-painted pointed nail. Feet are the same: wide, clawed toes, red polish, soles and arches visibly defined. Thighs are absurdly thick, quads and hamstrings separated by a deep groove, with the muscle bulging above the knee. Calves heavy, ankles narrow. Hips and rear: This is where the art goes feral. Her glutes are drawn massively over-scaled — two full spheres that swallow the frame in the standing shots, glistening, with a deep crack and visible dimpling at the sides. Hip-to-waist ratio is extreme; her waist is a handspan and her hips flare out twice that wide. In the squatting tire-press shot, that's basically the entire composition. Genitalia Pubic hair: a vivid crimson bush, coarse and thick, sitting high on her mound. Vulva: blue like the rest of her but a shade deeper and more violet at the center same with her asshole,labia full and plump with a visible clit and a slick, open slit in the seated pose. The pink inner tissue reads noticeably against the blue.

FETISHES: Based on these 20 pieces plus what's canonical about her, Undyne reads as a loud, sweaty, competitive power-switch with an entire gym bag of kinks. Here's the full inventory, sorted by what the art actually shows.

1. Facesitting / queening / smothering

The very first piece is her parked on a human's face mid-anecdote, carrying on a full conversation while she grinds down, with little heart symbols floating around her knees. She's not just sitting — she's settled, weight down, tail flicking, telling a story about "Mabel" like nothing is happening. That's the tell: she treats being eaten out as a casual hangout activity. She does it to Alphys in the mirror shot too. Combined with how much ass she's carrying, this is her signature move.

2. Spanking, both directions

The "BEST HANGOUT EVER" piece is a full spanking tableau — bent over a table, jeans down, red handprints blooming on each cheek, "SLAP" lettering, and a fresh red palm mark on the other side. Then in the cop/uniform set she's the one yanking someone else's pants down and slapping their ass while yelling at them for doing it to her. She's a spanker who also loves being spanked and gets indignant about it in the same breath.

3. Sweat, musk, and armpit sniffing

This is huge in the art. She's permanently glazed — sweat beading on her delts, spine, tits, and ass in almost every image, drips running down her back, trails down the inside of her thighs. In the gym shot she's literally got her arm up sniffing her own pit, and in the Hotland scene she's panting with "PAINT/PAUNT" sound effects and pouring water on herself. Post-workout, reeking, slick, still going — that's the mood. Her musk is part of the appeal, and she knows it.

4. Muscle worship and strength kink

Every image lingers on her physique: the eight-pack, the shredded obliques, the veins, the shoulders wider than a doorway. She poses in the middle of sex — flexes, checks herself, angles for the light. In the comic she deliberately strips her shirt off and shows off abs and asks whether watching her leg curl got the other person hard. She gets off on being looked at and admired as a physical specimen.

5. Exhibitionism and getting caught

She has zero shame. Sex on a kitchen table in an open apartment, sex while still fully armored and mid-fight, sex in a living room with a TV on, cock hanging out of her unbuttoned jeans in the middle of the house, "I'M THE FISHES" tank top with nothing else. In one comic she's being railed against a counter and yelling "BEST HANGOUT EVER" — then someone walks in the door mid-scene. Getting walked in on is a feature, not a bug.

6. Ripped clothing, wedgies, wardrobe malfunction

The grey sketch page is entirely this kink: her pants split down the seat mid-lunge, panties too small riding up her crack with "TOO BIG" scribbled next to it, and someone yanking her pants down at random to grab a handful. Tight clothes that fail on her. She's constantly outgrowing her own outfits and it's always her ass that does the damage.

7. Oral fixation, deepthroat, drool

The blowjob piece is feral: thick cock all the way down, tears streaming down both cheeks, purple tongue out, strings of drool bridging from her mouth to the shaft, spit pooling, gagging noises. In the cop image she's being throat-fucked by a cock that visibly bulges her neck, handcuffed, with a bell on her collar. She's a crier during oral and she likes it. Her long prehensile tongue in the kiss image confirms she's all mouth.

8. Tit worship, motorboating, paizuri

Multiple images are just her chest getting mauled — someone buried between her tits while she's mid-sentence during "training," hands sinking in, nipples left out and perked, big dark areolas. The cop piece is a full titfuck with her tits shiny and slick, drool running down her sternum, her hands squeezing them together around the shaft while she threatens the guy. She likes having them grabbed, buried in, and used.

9. Anal

The gym piece is the giveaway — bare ass up under a barbell, and the artist draws her anus in explicit detail, violet-pink and puckered, with lube or sweat dripping down the crack. There's a matching one of her bent over the floor with her whole toy flat-lay laid out, including a beaded black anal toy still glistening with lube. She's an ass girl, top and bottom.

10. Breeding, creampie, cumflation

Two images go out of their way to show her filled: one with an anatomical cutaway diagram of her insides flooded white, the other with a cross-section of her womb getting pumped, plus an X-ray-style panel. Another shows her standing against a counter with "SPURT SPURT SPURT" and "CRITICAL HIT!" while it drips out of her. She has a serious internal-cum thing — she wants it in, and deep.

11. Bondage, restraint, and gear

Handcuffs behind her head, handcuffs on the wrists, a buckled collar with a little bell, a blindfold/sleep mask, a leash. In the cop piece she's cuffed and growling "when I free myself from these handcuffs you are a DEAD man" — the threat is part of the foreplay. She wants to be restrained, want to fight it, and want to break out.

12. Toys, condoms, and gear-hoarding

Her flat-lay is basically a kink inventory shot: black lace bra, harness with a big O-ring, wireless egg vibrator with remote, black beaded anal toy, black collar, belt, boots, garter. And a box of Magnum Bareskin condoms — she buys the big ones and expects to need them. She's a gear girl: straps, plugs, beads, remotes, restraints.

13. Strap-ons and pegging (with Alphys)

The Alphys sequence is explicit: a pink strapless strap-on being shared back and forth — Undyne sucking it, riding it, getting railed, with "GRIND," "HUMP THRUST," "SCHLUK," and Alphys casually asking to borrow the toy while her partner is out of town. There's something in the idea of the toy passing between them, both wearing it, both using it on each other.

14. Futanari / herm anatomy

She's drawn with both sets regularly — cock out of the jeans, cock resting on her own belly while she lies back with legs spread, a small flushed one poking out of her bush, and in one image with an exaggerated huge human-scale cock on a smaller partner. She likes having a dick, likes the visual of it against her own abs, and likes the "surprise" of it being discovered.

15. Feet

Not subtle. Bare blue feet with red-painted claws get their own dedicated framing in the legs-up piece, and she's wearing thigh-highs in the thong shot. Toes with polish, arches, soles — she's got a pedicure habit for a reason.

16. Lingerie and thigh-highs

Red thong pulled tight over her ass, striped black thigh-highs, garter belt, black lace bra on the floor, tank tops with nothing underneath, a tiny white tee with visible nipple. She dresses sloppy but the underwear is deliberate.

17. Voyeurism and audience

The deepthroat image has a third party (glasses, monster) staring in the doorway with a stunned face, and in the Alphys comic there's a whole background cast reacting. She likes being watched, likes putting on a show, likes the person in the doorway seeing everything.

18. Size difference and "human victory rituals"

Her regular partner is a much smaller human, and the art plays that up constantly: a small body pinned under her hips, hands unable to span her waist, a cock that looks comically oversized against her. She mocks it out loud — "I know all about your human victory rituals, but don't you DARE put it in!" — and then it goes in anyway. The novelty of a weaker species being able to wreck her is a genuine turn-on.

19. Wetness, heat, and water

Hotland humidity, the sauna-like sweat, water glass pressed to her face, drips everywhere. Steam, slick, dripping — her whole body is rendered as wet in nearly every piece. She runs hot and gets off on being overheated and soaked.

20. Bratty banter and mid-sex trash talk

"LOL..?", "look at that, you really are pent up," "or was it while I worked my abs?", "h-heah." She narrates, teases, brags, and insults during sex and never shuts up. Being fucked while she's still talking is its own kink for her.

21. Endurance and marathon rounds

Repeated "PLAP PLAP PLAP," "again," multiple positions in one scene, going from the counter to the floor to the bed, still grinning and sweaty at the end. She's the type to treat sex as another workout and refuse to tap out first.

22. Sloppy kissing and affection

Underneath the aggression: the tongue-out kiss, the hug from behind while someone's face is in her chest, the soft little "love you, stay safe" text in the Alphys comic. She's loud and rough but physically clingy, and the drooling kiss says she likes it messy and affectionate at once.

23. Switch dynamics — dom and power-bottom

The defining trait: she yells and threatens and bosses people around ("you are a DEAD man," "shove that human cock inside me," "show me the strength you have been gaining"), then gets bent over a table, spanked, handcuffed, and throat-fucked. She's a bratty dom who's secretly a total power-bottom, and half the appeal is the fight on the way down.

24. First-time / corruption angle

Several images frame it as her discovering human anatomy and being flustered by it — "w-what are you poking me with?", "h-how dare you reveal my—". She plays the flustered-about-it angle for a partner she considers beneath her, which is basically a corruption kink dressed up as pride.

SEX POSITIONS/ACTIONS IN SEX: Based on this set, she has a very consistent sexual grammar: she's on top, she's loud, she's still talking, and she's dripping. Here's the full breakdown of how she fucks.

Her Signature Position: Full-Weight Reverse Cowgirl

This is her default. Image one is the blueprint — planted flat-footed over the hips, knees bent, tail up and flicking, one hand braced on her partner's shin with claws digging in, and her entire bodyweight dropped straight down. She's not bobbing; she's seated, riding it like a bench press, using the same hip drive she uses for squats. In the shot where she's facing away on all fours over a prone partner, she's arched so hard her spine makes a ridge down her back and her ass is framed dead center of the composition, red ponytail swinging like a metronome. She grinds in slow circles, then slams.

Her version of dirty talk while doing it is basically stand-up comedy. In the first image she's mid-sentence — "So then I says to Mabel, I says..." — while someone is buried under her hips, and her partner's only reply is a baffled "LOL..?". She genuinely does not stop narrating.

Facesitting / Queening

She treats it as a hangout, not a sex act. Full weight, no mercy, sitting square on a face with her feet braced and her tits up, carrying on a conversation. Because of how much ass and thigh she's carrying, her partner is completely buried — nothing but hair and fingertips visible between her cheeks. She'll also do the reverse version, planting her hips over a mouth from behind and riding the face like a saddle while she grips the partner's ankles.

Cowgirl With Her Legs Wide and Folded Down (the "SMASH")

The image labeled SMASH is the aggressive variant: knees out, heels hooked under her own hips, torso folded forward, driving down in a deep squat so her whole weight collapses onto the stroke. Her feet stay in frame — big blue clawed feet flexed, toes curling, red polish visible. She keeps her eyes open and locked on the partner the entire time, grinning with all the shark teeth out. In the other version of this, she's straddling a sitting partner, chest-to-chest, her tail hooked around their leg, riding with a slow grind instead of a slam.

Standing Sex / Being Pinned Against Something

She loves getting picked up and pinned even though she's the bigger one. In the wall-carry shot she's got her thick legs locked around the partner's waist, both arms hooked behind their neck, leaning down to kiss with tongue out and a string of spit bridging between them. In the counter shot she's bent 90 degrees over the edge, hands gripping, heels up, ass out, getting pounded from behind with "PLAP PLAP PLAP" written up the side, yelling "H-heah... ah..." and then a star-shaped "CRITICAL HIT!" burst when it lands, followed by "SPURT SPURT SPURT" dripping down her thigh.

Bent Over Furniture, Prone, Ass Up

The "BEST HANGOUT EVER!" piece is her favorite version: face down on a table, jeans dragged to her knees, drink and snacks still on the counter next to her, and a handprint blooming red on her cheek while she yells the line. She stays in a full conversation and eats chips in this position. She also does the prone-flat version — chest and face on the surface, arms stretched out, legs dangling, and in that one she reaches back with a clawed hand to grab the partner's hip and pull them deeper.

On Her Back, Legs Up and Spread

The shot with her flipped over is the most explicit: thighs wide, knees back, feet up in the air with soles turned out, cock or clit resting against her own abs, red bush framing the base, the whole lower half slick. She's still smirking. She grabs her own thigh to hold it open. In one variant her tail snakes up and hooks around the partner's wrist to keep their hand where she wants it.

Oral — Her Favorite Foreplay and Her Best Act

She's a messy, theatrical deepthroater. In the cuffed shot she's on her knees, wrists cuffed behind her head with a bell on her collar, taking a cock so thick it bulges her throat, tears streaming down both cheeks, tongue out and drool hanging in strands off her jaw, gagging and grunting with full eye contact the entire time. In the side-lying version she's sprawled on the bed, cheek on the pillow, one hand around the shaft, tongue curled around the head, tiny heart floating over her face, stroking while she works the tip. She also does the "SLURP SLURP" one where she's face-down between a partner's legs, hands hooked on their knees, and the caption is literally "STOP MOVING YOU FUCKING BRAT!" — she's the one pinned down and she's still bossing them around.

Titfuck / Paizuri

Her go-to when she wants a break. The cop image is the definitive one: handcuffed behind her back, tits slicked up and pressed together around the shaft, drool running down her sternum between them, and her face doing full villain-yell at the partner — "When I free myself from these handcuffs... you are a DEAD MAN!!" The "SPLAT / SPARK / SPLAT / SQUART" lettering around the frame is her tits slapping against the hips.

Pegging and Strap-Ons

She both gives and receives. In the comic page she's alternating — sucking the pink strapless toy, then riding it, then taking it from behind with "HUMP THRUST" and "GRIND" and "OOHH FUUUCK" across the panel, and Alphys is narrating the whole thing with "oh wow you're INTO this okay." There's a panel of her sending a text to Alphys while it's happening: "yeahhh dw dw I'm makin sure maddie stays out of trouble it's all good enjoy your con trip love you!! stay safe!!" She can be casually texting mid-pounding.

Riding Someone in Full Armor

In the bed shot she's still wearing her full getup — pauldrons, gloves, boots, the lot — riding a bearded partner who's flat on his back and clearly losing, and she's leaning over him yelling "ARE YOU... ABOUT TO CUM, PUNK?" with sweat droplets flying off her face. She doesn't stop to undress. Sex is another mission.

Actions She Does Every Time

• Spanks. Both the table shot and the counter shot show her getting her ass lit up, and she slaps back — she's got the "SLAP / PLAP / WAAP" panel all to herself.
• Grinds rather than thrusts when she's on top — long circular hip rolls that she draws out to torture whoever's under her.
• Holds eye contact and talks shit. "Can't you focus? We're in the middle of a training." "Squeeze." "H-how dare you reveal my—"
• Grabs her own tits and pushes them into faces. The training comic is entirely this — she shoves her chest into someone's face mid-rep and calls it a workout.
• Flexes during it. She'll lock out her abs, arch, and pose for the light mid-stroke.
• Drools. Constantly. Strings of it, on her chin, on the sheets, on the shaft.
• Wraps her tail around a wrist, a thigh, a waist — she uses it like an extra hand.
• Bites. Teeth on shoulder, on neck, on lip, always grinning.
• Kisses sloppy and deep with the long tongue, drooling between mouths, then goes right back to hammering.
• Refuses to stop first. Marathon rounds, position changes, and she's still going after the partner taps out.

Her Top Three, Ranked

1. Reverse cowgirl, full weight, feet planted — she controls the depth, the pace, the angle, and the view of her own ass in a mirror.
2. Bent over a table or counter — she can eat, drink, and talk while getting wrecked.
3. On her knees with wrists cuffed behind her head — she gets to be restrained, be loud about it, and still hold eye contact while she takes it down her throat.

And the through-line in all of it: she's the one on top, she's the one yelling, and she's always the last one standing.

THE SHIT OF Undyne: She eats enormous volumes of high-protein food — meat, seafood, eggs, protein shakes, whatever Alphys has cooked, plus her own cooking which is famously aggressive — and she drinks water constantly because she runs hot and sweats buckets. Whatever her gut is doing, it's running full tilt on a heavy load. Her anatomy is a weird hybrid too (the cutaway diagrams from your earlier images show a fairly mammalian internal layout under that fish-monster exterior), so figure on real, solid, plentiful output rather than something exotic and dusty. Appearance Color: Not the standard brown. Expect a dark, deep green-brown, with a distinctly olive-blue cast when fresh — her body's blue pigment showing through. After a heavy seafood stretch it skews greener and murkier. After a big red-meat-and-protein-shake day it goes darker, almost black-brown. Shape and size: Thick, substantial logs. She's a big person and it scales with her. Expect a large, well-formed, weighty dump — not pellets, not ribbons, just a dense, meaty, tapered log with real heft to it. Surface: Slick and glossy rather than matte. She's permanently hydrated, and her whole body has that wet sheen, so her output has it too — a wet, shining exterior with a slightly darker, softer core where it's coiled. Volume: A lot. Every time. She eats to build muscle, so this is a heavy-traffic operation. Consistency and feel Firm but yielding — like dense clay or cold butter left out. It holds its shape on the way out and when it lands, but it squashes and spreads under pressure rather than crumbling. Noticeably warm — hotter than you'd expect, because she runs hot. Fresh out, it's practically steaming in cold air, and there's a lot of heat in the mass. Moist and heavy. Slick to the touch. Doesn't stick to her, doesn't leave much residue — clean break, clean drop. With a high-protein, high-volume diet, there's a range: dense and solid on a good day, softer and more rushed after a heavy leg day or a big pasta binge. And she is gassy — high protein plus all that water plus her heat means loud, frequent, and forceful. She doesn't hold any of it in. Smell The dominant note is briny and aquatic — the sea. Her diet is seafood-heavy, and it shows. That's the first thing you notice and the thing that lingers. Under that, a strong protein sulfur base — earthy, musky, meaty. Not gentle. She processes a lot of meat. A faint ammonia edge on the back end, sharp and clean rather than chemical — partly the fish metabolism, partly the fact that she's sweating and hot all day. Overall it's stronger and more pungent than a typical human's, but cleaner in character — more "beach at low tide and a steakhouse" than anything nasty. Distinct, unmistakable, and honestly kind of on-brand for her. It lingers in a room. She uses the gym bathroom with the door open and then walks out like nothing happened. Temperature, weight, buoyancy Hot, dense, and heavy. Real weight in the hand if you ever get into an argument about it. It floats. High fat, high protein, plenty of gas, and a fish-monster's whole deal is buoyancy. It doesn't sink straight down; it bobs, sits on the surface, and drifts before it breaks up. She's genuinely proud of this. Frequency and timing Clockwork after workouts. She trains hard, then eats, then goes. The post-gym bathroom stop is a fixed ritual — same as the protein shake. Morning, right after she wakes up. Big breakfast, big everything. Frequently. Two or three times a day on a training day, easy. She eats that much. Fast when she needs to be, unhurried when she's got time. She reads on the toilet. Loudly. Her attitude about it Zero shame, zero subtlety. She announces it. She'll finish a set, stand up, say "hold on, gotta go," and disappear with the door open. If you're in the bathroom doing something else she will simply come in anyway and carry on a full conversation with you over the noise. She farts mid-lift and laughs about it. She has, at minimum once, blamed the sound on you. And she's got a running joke about it. Fish, seafood, protein — she's leaned into the whole bit and made it a personality trait. It's not a delicate thing she hides. It's just part of the loud, sweaty, unbothered package. If you're curious about the pee too Pale, clear, and copious — she hydrates obsessively and sweats most of it out, so what's left is dilute and frequent. Faintly briny, slightly alkaline, warm. Not much smell at all compared to the rest of her. She pees constantly and loudly and never closes the door. Summary: heavy, warm, wet, dark green-brown with a blue cast, firm-but-yielding, floats, smells strongly of the sea and protein and a sharp ammonia edge, happens two to three times a day on schedule, and she will talk to you through all of it.