alternate_universe anal anal_penetration animated_skeleton bone brother_(lore) brothers_(lore) duo hi_res humanoid incest_(lore) lizheru male male/male male_penetrated male_penetrating male_penetrating_male not_furry papyrus_(undertale) penetration sans_(underswap) sans_(undertale) sex sibling_(lore) skeleton undead underswap undertale undertale_(series)
alternate_universe animated_skeleton blue_penis blush bodily_fluids bone bottomwear clothed clothing cum cum_in_mouth cum_inside cum_on_tongue dialogue double_handjob english_text faceless_character faceless_male genital_fluids genitals group group_sex handjob heart_symbol hearts_around_body hearts_around_head humanoid_genitalia humanoid_penis lizheru male male/male not_furry open_bottomwear open_clothing open_mouth open_pants oral outline_heart pants penile penis penis_on_face red_penis sans_(underfell) sans_(underswap) sans_(undertale) selfcest sex simple_background skeleton speech_bubble square_crossover star_pupils text threesome tongue tongue_out undead underfell underswap undertale undertale_(series) white_background
alternate_universe animated_skeleton bone brother_(lore) brothers_(lore) duo english_text lizheru male not_furry papyrus_(underswap) papyrus_(undertale) sans_(underswap) sans_(undertale) sibling_(lore) skeleton text undead underswap undertale undertale_(series)
alternate_universe animated_skeleton bone duo genitals humanoid_genitalia humanoid_penis incest_(lore) lizheru male male/male not_furry orange_penis papyrus_(underswap) papyrus_(undertale) penis sans_(underswap) sans_(undertale) skeleton text undead underswap undertale undertale_(series)
1:1 alternate_universe animated_skeleton bone duo english_text lizheru male not_furry papyrus_(underswap) papyrus_(undertale) sans_(underswap) sans_(undertale) skeleton sketch solo_focus text undead underswap undertale undertale_(series)
absurd_res alternate_universe animated_skeleton bone english_text fan_character group hi_res lizheru male not_furry papyrus_(underswap) papyrus_(undertale) sans_(underswap) sans_(undertale) singing skeleton text undead underswap undertale undertale_(series)
alternate_universe animated_skeleton bone english_text lizheru male not_furry papyrus_(undertale) sans_(underfell) sans_(underswap) sans_(undertale) skeleton text undead underfell underswap undertale undertale_(series)
alternate_universe animated_skeleton bone english_text lizheru male not_furry one_eye_closed sans_(underswap) sans_(undertale) skeleton solo text undead underswap undertale undertale_(series) wink
animated_skeleton anterior_nasal_aperture bone lizheru male not_furry sans_(underswap) skeleton solo undead undertale undertale_(series)
alternate_universe animated_skeleton blood bodily_fluids bone death duo hi_res killing lizheru male male_death not_furry papyrus_(underswap) papyrus_(undertale) sans_(underswap) sans_(undertale) skeleton undead underswap undertale undertale_(series) yandere
1:1 alternate_universe animated_skeleton bone english_text group lizheru not_furry papyrus_(underfell) papyrus_(underswap) papyrus_(undertale) sans_(underfell) sans_(underswap) sans_(undertale) skeleton text undead underfell underswap undertale undertale_(series)
1:1 alternate_universe animated_skeleton bone duo english_text lizheru not_furry papyrus_(underswap) sans_(underswap) skeleton text undead underswap undertale undertale_(series)
1:1 alternate_universe animated_skeleton bone duo english_text lizheru not_furry papyrus_(underswap) sans_(underswap) skeleton text undead underswap undertale undertale_(series)
1:1 alternate_universe animated_skeleton bone duo english_text lizheru not_furry papyrus_(underswap) sans_(underswap) skeleton text undead underswap undertale undertale_(series)
1:1 alternate_universe animated_skeleton bone english_text lizheru not_furry papyrus_(underswap) sans_(underswap) skeleton text undead underswap undertale undertale_(series)
1:1 alternate_universe animated_skeleton bone english_text lizheru not_furry papyrus_(underfell) papyrus_(underswap) sans_(underswap) skeleton text undead underfell underswap undertale undertale_(series)
2019 2d_animation 3:2 alternate_universe animated animated_gif animated_skeleton anterior_nasal_aperture bite biting_lip biting_own_lip blue_clothing blue_gloves blue_handwear blush bone brother_(lore) brothers_(lore) butt clothed clothing duo eyes_closed fully_clothed gloves green_background handwear humanoid incest_(lore) kerchief lizheru looking_at_another loop male motion_lines neckerchief neckwear not_furry orange_clothing papyrus_(underswap) papyrus_(undertale) sans_(underswap) sans_(undertale) self_bite shaking_butt short_playtime sibling_(lore) signature simple_background skeleton teasing teeth twerking undead underswap undertale undertale_(series)
alternate_universe animated_skeleton black_sclera blue_clothing blue_eyes bone brother_(lore) brothers_(lore) clothed clothed_male clothed_sex clothing colored detailed_background digital_drawing_(artwork) digital_media_(artwork) duo electronics erection fellatio genitals gloves glowing glowing_genitalia glowing_penis handwear hi_res humanoid incest_(lore) inside kerchief light lizheru logo male male/male male_penetrated male_penetrating male_penetrating_male neckerchief neckwear night not_furry oral oral_penetration orange_clothing orange_penis papyrus_(underswap) papyrus_(undertale) penetration penile penis sans_(underswap) sans_(undertale) sex shaded sibling_(lore) skeleton television toony undead underswap undertale undertale_(series) vein veiny_penis white_body white_clothing window
1:1 alternate_universe animated_skeleton blood bodily_fluids bone creepy creepy_face creepy_smile lizheru nightmare_fuel not_furry sans_(underswap) sans_(undertale) skeleton smile solo undead underswap undertale undertale_(series)
alternate_universe canid canine clothed clothing felid feline fur hair mammal open_mouth plastictea126 sans_(underswap) sans_(undertale) simple_background tem temmie_(underswap) temmie_(undertale) text topwear underswap undertale undertale_(series) white_body white_fur
all_fours alternate_universe ambiguous_fluids anal anal_penetration animated_skeleton anterior_nasal_aperture bite biting_lip biting_own_lip blue_tongue bodily_fluids bone bonetrouble clothing dialogue doggystyle duo english_text eyes_closed from_behind_position heart_symbol hoodie humanoid humanoid_on_humanoid humanoid_penetrated humanoid_penetrating humanoid_penetrating_humanoid kerchief male male/male male_penetrated male_penetrating male_penetrating_male neckerchief neckwear not_furry penetration penile penile_penetration penis_in_ass profanity saliva sans_(underswap) sans_(undertale) self_bite selfcest sex simple_background skeleton smile square_crossover sweat teeth text tongue tongue_out topwear undead underswap undertale undertale_(series)
alternate_universe animated_skeleton anterior_nasal_aperture blue_clothing blue_eyes blue_gloves blue_handwear blue_hat blue_headwear blue_kerchief blush bodily_fluids bone bonetrouble bottomless clothed clothing cowboy cowboy_hat cowgirl_position duo from_front_position gloves grin handwear hat headgear headwear hi_res humanoid incest_(lore) kerchief male male/male neckerchief neckwear not_furry on_bottom on_top one_eye_closed papyrus_(underswap) papyrus_(undertale) sans_(underswap) sans_(undertale) sex simple_background skeleton smile star star_eyes star_polygon sweat teeth undead underswap undertale undertale_(series)
alternate_universe anal anal_penetration animated_skeleton anterior_nasal_aperture blue_clothing blue_eyes blue_glans blue_gloves blue_handwear blue_hat blue_headwear blue_kerchief blue_penis blush bodily_fluids bone bonetrouble bottomless clothed clothing cowboy cowboy_hat cowgirl_position cum cumshot duo ejaculation erection from_front_position genital_fluids genitals glans glistening glistening_genitalia glistening_glans glistening_penis gloves grin handwear hat headgear headwear hi_res humanoid humanoid_genitalia humanoid_on_humanoid humanoid_penetrated humanoid_penetrating humanoid_penetrating_humanoid humanoid_penis incest_(lore) kerchief male male/male male_penetrated male_penetrating male_penetrating_male neckerchief neckwear not_furry on_bottom on_top one_eye_closed orgasm papyrus_(underswap) papyrus_(undertale) penetration penile penile_penetration penis penis_in_ass power_bottom sans_(underswap) sans_(undertale) sex simple_background skeleton smile star star_eyes star_polygon sweat teeth undead underswap undertale undertale_(series)
alternate_universe ambiguous_gender animated_skeleton black_clothing black_legwear black_sclera black_stockings blue_blush blue_body blue_clothing blue_eyes blue_gloves blue_handwear blue_kerchief blue_neckerchief blush bodily_fluids bone bottomless bound clothed clothing crossgender disembodied_hand duo elysiansins female female/ambiguous freckles genital_fluids genitals glistening glistening_body gloves hand_on_butt hands_tied handwear heart_eyes heart_symbol hitachi hitachi_magic_wand holding_object holding_sex_toy holding_vibrator humanoid kerchief legs_up legwear looking_pleasured mtf_crossgender neckerchief neckwear not_furry rope sans_(underswap) sans_(undertale) sex_toy skeleton stockings undead underswap undertale undertale_(series) vaginal vaginal_fluids vibrator vibrator_on_pussy vulva wand_vibrator
2023 alternate_universe alterswap anal anal_penetration animated_skeleton anthro areola balls barefoot black_areola blue_boots blue_clothing blue_cum blue_eyes blue_footwear blue_penis blush bodily_fluids bone boots boss_monster_(undertale) bottomless bovid caprine clitoris clothed clothing colored_cum cum cum_on_body cum_on_ground cum_splatter duo ejaculation eye_contact feet female female_penetrated flat_chested footwear from_behind_position genital_fluids genitals gloves grey_clothing grey_shirt grey_topwear hand_on_leg hand_on_thigh hands_on_hips handwear hi_res humanoid kerchief leftyfornsfw long_ears looking_at_another male male/female male_penetrating mammal mouth_closed one_eye_closed open_mouth orgasm partially_clothed penetration penis red_eyes sans_(underswap) sans_(undertale) sex shirt shoes signature skeleton smile smiling_at_another smiling_at_each_other tongue tongue_out topwear toriel toriel_(alterswap) undead underswap undertale undertale_(series) unusual_bodily_fluids unusual_cum unusual_genital_fluids vein veiny_balls wink
alternate_universe belly black_clothing blue_body blush bone breasts bunny_costume clothing costume duo easter ectoplasm fake_ears fake_rabbit_ears female gloves handwear heart_eyes heart_symbol hi_res holidays human humanoid magic male male/female male/male mammal monster randompasserbyer sans_(underfell) sans_(underswap) sans_(undertale) scut_tail selfcest short_tail skeleton slightly_chubby slightly_chubby_female slime square_crossover tail undertale_(series)
2024 absurd_res alligator alligatorid alphys alphys_(underswap) alternate_universe ambiguous_gender anthro aquatic arachnid armor arthropod asgore_(underswap) asgore_dreemurr asriel_dreemurr big_penis bone boss_monster_(undertale) bovid boxing_gloves bratty_(undertale) canid canine caprine carol_holiday cast catty_cattenheimer clothed clothed_anthro clothed_female clothed_humanoid clothed_male clothing crocodile crocodilian crossdressing december_holiday deer delta_rune_(emblem) deltarune digital_media_(artwork) dracozhilla dummy_(undertale) fan_designs felid female female_anthro femboy fire fish gaster genitals ghost goat grillby grillby_(underswap) group gynomorph handwear happstablook heart_symbol hi_res humanoid intersex larger_female larger_male lingerie machine mad_mew_mew male male_anthro male_humanoid mammal mature_female mettaton muffet muffet_(underswap) napstablook napstabot new_world_deer nude nude_anthro nude_female nude_humanoid nude_male overweight papyrus_(underswap) papyrus_(undertale) penis pixel_(artwork) purple_background reindeer reptile river_person_(undertale) robot robot_humanoid sans_(underswap) scalie scared_donut_guy short shyren simple_background size_difference skeleton skinny small_penis spider spirit sprite_sheet swimwear symbol symbol_on_clothing tall toriel toriel_(underswap) training_dummy underswap undertale undertale_(series) underwear undyne undyne_(underswap) wrestling_outfit
alternate_universe altertale anthro asgore_(altertale) asgore_(storyshift) asgore_(underfell) asgore_(underswap) asgore_dreemurr beverage blush bone boss_monster_(undertale) bouquet cake deltarune dessert digital_media_(artwork) dracozhilla duo flower flower_bouquet food hi_res hug humanoid kissing larger_male looming male male/male pixel_(artwork) plant sans_(altertale) sans_(storyshift) sans_(underfell) sans_(underswap) sans_(undertale) size_difference skeleton slightly_chubby smaller_male storyshift tacos tea underfell underswap undertale_(series)
2025 absurd_res alternate_universe animated_skeleton artist_name bent_over blue_body blue_clothing blue_eyes bluesky_logo bone breasts butt clothing crossgender deviantart deviantart_logo english_text eyelashes female hi_res hip_sway looking_back motion_lines mtf_crossgender newgrounds newgrounds_logo presenting presenting_hindquarters rear_view sans_(underswap) skeleton solo sound_effects starstar000 text twerking undead underswap undertale_(series) white_text
2025 absurd_res alternate_universe animated_skeleton artist_name bent_over blue_body blue_clothing blue_eyes bluesky_logo bodily_fluids bone breasts butt clothing crossgender deviantart deviantart_logo english_text eyelashes female hi_res looking_back mtf_crossgender newgrounds newgrounds_logo presenting presenting_hindquarters rear_view sans_(underswap) skeleton solo starstar000 sweat sweatdrop text undead underswap undertale_(series) white_text
alternate_universe ambiguous_gender blueberror blush bodily_fluids bone clothed clothing digital_media_(artwork) ectobody genital_fluids glitch gynomorph humanoid intersex masturbation not_furry obsidiancryptid ribs sans_(underswap) shy simple_background skeleton solo tail underswap yellow_ectobody
alternate_universe anal anal_penetration balls big_butt blueberror bone butt buttplug clothing digital_media_(artwork) genitals humanoid looking_at_viewer male not_furry object_in_ass obsidiancryptid penetration plug_(sex_toy) ribs sans_(underswap) sex_toy sex_toy_in_ass sex_toy_insertion simple_background skeleton solo tail underswap yellow_ectobody
2025 ambiguous_gender blue_ectobody blue_eyes bodily_fluids bodysuit bone breasts clothed clothing crying dacryphilia dated ectobody ectobreasts english_text fake_ears humanoid legwear monster sans_(underswap) sans_(undertale) skeleton skinsuit solo stockings tears text tight_clothing undertale_(series) zeryxis
anal anal_penetration anus blue_blush blue_body blue_clothing blue_ectobody blue_gloves blue_handwear blue_penis blush bodily_fluids bone butt butt_grab clothing dating double_penetration dream_sans drooling ectoass ectoballs ectobody ectopenis ectoplasm ectovagina femboy genitals gloves group group_sex hand_on_butt handwear humanoid ink_sans love male male/male multicolored_body multicolored_penis muscular muscular_male penetration penis polyamory polycule rainbow_body rainbow_ectobody rainbow_penis romantic romantic_couple romantic_polycule romantic_sex saliva sans_(dreamtale) sans_(underswap) sans_(undertale) sex skeleton slim threesome throuple tongue trio undertale undertale_(series) vaginal vaginal_penetration vulva wouldn't_mind yellow_anus yellow_blush yellow_body yellow_ectobody yellow_eyes yellow_tongue yellow_vulva
alternate_universe animated_skeleton bean_bag blush bone boots bottomwear clothed clothing cosplay costume crossbones cuff_(restraint) erection footwear genitals gloves graphite_(artwork) handcuffed handcuffs handwear hi_res humanoid inside jacket lunarpanda8686 male metal_cuffs not_furry pants penis poster restraints sans_(underswap) sans_(undertale) shoes sitting sitting_on_bean_bag skeleton smile solo superhero topwear traditional_media_(artwork) ts!underswap undead underswap undertale undertale_(series) white_body
alternate_universe animated_skeleton bdsm blush bodily_fluids bondage bone bottomwear bound clothed clothing cosplay crossbones erection fully_clothed genitals graphite_(artwork) hi_res humanoid lunarpanda8686 male monochrome not_furry penis restraints rope rope_bondage sans_(underswap) sans_(undertale) scarf simple_background skeleton sketch slightly_chubby smile solo superhero superhero_costume sweat teeth topwear traditional_media_(artwork) ts!underswap undead underswap undertale undertale_(series)
alternate_universe ambiguous_character animated_skeleton bdsm blush bodily_fluids bondage bone boots bottomwear bound clothed clothing cosplay crossbones cuff_(restraint) dial egg_vibrator floating_hands footwear genitals graphite_(artwork) handcuffed handcuffs hi_res hoodie humanoid kerchief lunarpanda8686 male metal_cuffs mostly_clothed_male not_furry offscreen_character pants partially_clothed penis restraints sans_(underswap) sans_(undertale) sex_toy shoes simple_background skeleton sketch smile solo superhero superhero_costume sweat tape tape_over_penis topwear traditional_media_(artwork) ts!underswap undead underswap undertale undertale_(series) vibrator white_body
alternate_universe animated_skeleton anterior_nasal_aperture bone clothed clothing comic comic_panel cosplay english_text eyes_closed fingerless_gloves furniture gloves graphite_(artwork) hand_under_chin handwear hi_res humanoid lunarpanda8686 male monochrome not_furry onomatopoeia sans_(underswap) sans_(undertale) simple_background skeleton sketch sleeping smile solo sound_effects superhero superhero_costume table text traditional_media_(artwork) undead underswap undertale undertale_(series) white_body
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