This is where there's something romantic going on between a human and something that, for whatever reason, looks equally human but is actually nonhuman (Little Bit Beastly, shapeshifting, or genetic engineering). The romance element can be anything from subtext to full blown relationships, and for some reason are never treated as if there's any reason why they should be squicky at all. In fact, in some cases, they actually come across as sweet and touching, and the dominant thought on the reader's mind is usually "awww," which probably wouldn't be the case if the nonhuman in question wasn't usually humanoid in appearance.
- Ayakashi Triangle: Most ayakashi are sapient, but romance with a human is only considered when they have humanoid form:
- Garaku looks human (rather arbitrarily, as tsukumogami like him are usually Animate Inanimate Objects), fell in love with Mei, and Matsuri sees him as a romantic rival for Suzu's affection.
- When Shirogane appears before Lu in Matsuri's male form, calling himself "Shiromatsu", she ends up falling in love with him. Shirogane doesn't reciprocate, as his natural form is a cat (and he was original a non-sapient one), not to mention he's much older than the teenage Lu.
- Ranma ½: The Musk Dynasty turned animals into women using the Springs in order to have children with them.
- All the relationships between owners and their persocoms in Chobits.
- In Man's Best Friend, a Yaoi manga by Kazusa Takashima, a dog falls in love with his teenage-boy owner and gains the ability to transform into a hunky man.
- Played strangely in Sailor Moon: Chibi-Usa and Kakeru have some romance hinted with Pegasus/Helios and Luna, respectively. The latter both have human forms, but spend most of their time on-screen and with their counterpart as a cat and winged horse. Apparently, if you're going to be into Interspecies Romance in this series, you're going to have to be okay with their normal form before you ever get to see them in a human form.
- Inuyasha has a number of romances between humans and (half)-youkai, but the youkai are always either naturally humanoid (Inuyasha, Koga) or have a humanoid Shapeshifter Default Form (Sesshomaru, Inuyasha's father).
In a slightly comical aversion, the Thunder Brothers' father was visually indistinguishable from a human (like Hiten), but their mother was a squat, yellow-skinned humanoid with a large conical head (like Manten). For their species of youkai, this is apparently completely normal.
- Since familiars in Lyrical Nanoha were originally animals such as cats or wolves, any case where a familiar exhibits feelings for a human and vice versa falls under this, such as the Ho Yay between Arf and Fate, or Liezelotte showing much affection towards Chrono.
- In The Twelve Kingdoms (both anime and novel) there's a fair bit of subtext between Rakushun and Youko...and Rakushun is a giant, vaguely humanoid rat (he's just a rodent of unusually large size that can stand on his hind legs) who can turn into a human at will, though he prefers his rat form. There's also a not-so-implied unrequited love between the former Queen of Kei and Keiki, the shape-shifting Unicorn...and then there are in turn shippers who swear by a Keikix Youko coupling.
- A filler episode of Slayers has a man fall in love with a fish person. They want to find a potion that will 'allow them to live together', thinking this means that it will turn the fish-woman into a human woman. While this is true, it also turns the man into a fish-man. They are perfectly happy with this.
- Happens many times in Dragon Half. Vina's mother (a slime) fell in love with the king (since his dumpy head sort of looked like a slime) and used a potion to turn human... except their daughter was born as a slime too, and then has to use magic to (temporarily) maintain a human form. Rouche the knight meanwhile fell in love with the dragon he was sent to slay, Mana, and eloped with her. (Humorously, although she can turn almost-human, he appears to have fallen for her in her dragon form...) Mink wants to become human too, even though she's almost completely human except her wings, tail and horns (and super-strength), but this is mainly because her love interest is an overzealous dragon slayer.
- There was possibly one story, Krypto the Superdog turned into a human and formed a relationship with a woman.
- Pre-Crisis Supergirl owned a super-powered, intelligent horse named Comet. Comet was really a centaur called Biron who'd been cursed so that at any one time he had to be all horse or all man. And he had a crush on Kara.
- Lesbian Comet is the Post-Crisis version, who was a lesbian comedienne who'd combined with a male superhero with horse-DNA to form an Earth Angel in the same way as Matrix Supergirl combined with Linda Danvers. (S)he could alternate between the two forms. Supergirl was attracted to Comet, but somewhat taken aback by Andi.
- Alan Moore once wrote a story about Swamp Thing's girlfriend noting that Lois and Superman have essentially the same relationship as they do.
- After she got arrested for "Crimes against nature", leading to Swamp Thing using his plant powers to turn Gotham City into a jungle, Batman pointed this out to the mayor, who panicked and dropped the charges.
- X-Men: Beast's girlfriend left him when he went from blue-hairy-ape-man-thing to blue-hairy-cat-man-thing, because even with all the fantastic racism, that was the point that people started comparing their relationship to bestiality. Later, poor Beast gets feelings for a cat-girl, who actually turned out to be more cat than girl. Seems mutancy is not just restricted to homo sapiens.
- XXXenophile goes out of its way to transform one housecat into a human before getting him involved with a human woman. This may have been more about scale than anything else, given that the same woman gets involved with a shapechanging Fairie Queen that goes much, much further from the typical form factor trying to squick her out.
- It was definitely about scale, as "Cat of the Curse People" (no, 'cat' and 'curse' are not supposed to be swapped in that title) has human woman/male werepanther sex.
- This is also the comic which features a human having sex with a centaur several times before the centaur had sex (offscreen) with a horse—the 'curse' of being part horse transferred with sex, so the horse wound up with six legs afterwards.
- Reversed in a separate comic, where a human who has had his brain transplanted into the body of a dog falls into despair that he might not transform back, among other things thinking that his girlfriend should probably see someone else. Here, scale was not an issue.
- Tank Girl gives us the relationship between the heroine and her mutant kangaroo boyfriend Booga. He behaves like any human, and the issue of their Interspecies Romance is rarely discussed.
- Inverted in Beauty and the Beast, although that one still gets lots of d'awwww....
- Jim Butcher's Fool Moon, in covering the entire range of Our Werewolves Are Different (minus the traditional "get bitten and become a werewolf" thing, which really is only in the movies), includes wolfweres (wolves that can take human form rather than the other way around). And one of them has a romantic relationship with a human who's cursed to turn into a wolf.
- Poledra in the Belgariad. She's a wolf, who takes the form of a human because she loves Belgarath, a human who can take the form of a wolf. We get very little explanation for why she is the only wolf known able to do this and live for thousands of years. Her expressions on the subject, irritating as they are ("what is time to a wolf?") are less than informative.
- Apparently wolves, like humans, have the potential to become sorcerers, who get functional immortality and Voluntary Shapeshifting as inherent abilities. Poledra is either the only wolf to really get the hang of her powers, or the only one to actually take an interest in human affairs. It's hinted that she was called as a disciple.
- There's another example from the Trickster duology written by Tamora Pierce - Nawat is a crow who becomes human after falling in love with the protagonist. At first he continues to act somewhat like a crow, but she doesn't start to return his affections until some time later, once he's started to act more human.
- Terry Pratchett plays with this in Discworld.
- Ludmilla Cake and Lupin in Reaper Man. She's a human who turns into a Wolf Woman at full moon. He's a wolf who turns humanoid at full moon. They apparently have a relationship for one week a month, and the rest of the time Lupin is kind of Ludmilla's mother's pet dog. Which is a lot squickier written like that than it was in the book...
- Another werewolf, Sergeant Angua, has a romantic relationship with Carrot, dwarf-raised human (and, in the eyes of his family, a dwarf himself). The books mention that relationships between humans and werewolves are usually extremely difficult, but they manage to make it work.
- Inverted The Fifth Elephant, where a wolf called Gavin (well, he once ate someone named Gavin) is said to have had a very Carrot-like relationship with Angua. The Squick mitigation comes less from him being a smart wolf, and more Angua not being human all of the time she's with him.
- That, and the fact that it's implied that Gavin is the descendant of a yennork—a werewolf who isn't able to morph.
"You see, a yennork would go off and be a human or be a wolf but they'd still be carrying the werewolf...blood, and then they'd marry and have children...or pups...and, well, that's where the fairy-tale monsters come from. People with a bit of wolf and wolves with that extra capacity for violence that is so very human." She sighed, and glanced momentarily at Gavin.
- That, and the fact that it's implied that Gavin is the descendant of a yennork—a werewolf who isn't able to morph.
- Nanny Ogg's pet cat Greebo, in Witches Abroad, picked up a new skill: he can turn into his human male equivalent, and invokes All Girls Want Bad Boys. He retained the skill, and uses it again in Maskerade.
- Any one person that's in love with a werewolf in the Twilight universe. Sure, they originally were human so it may be a subversion in that regards, but they're still large wolf like things that don't really look like wolves in the movies.
- Numerous relationships between humans and aliens on Star Trek. Captain Kirk was famous for
fucking aliens"Boldly Coming where no man has gone before".
- Odo and Kira on Star Trek: Deep Space Nine. She's a human with ridges on her nose, he's naturally a puddle of goo.
- Both subverted and played straight in Farscape. John's dad tells Aeryn outright that he isn't bothered by her relationship with John since he doesn't think of her as an alien. However, in the TV program they intercept from Earth later, there is quite a lot of debate over whether or not Aeryn is pregnant with John's child and how Squicky it would be if she was.
- In Buffy the Vampire Slayer we have Buffy who has relationships with vampires. And it's an ongoing joke with Xander that demons are attracted to him.
- Not to mention that Willow's first on-screen relationship was (unknowingly) with a demon who had been turned into a magical book, who was then turned into computer data, who then turned into a robot...
- The Doctor and Rose in Doctor Who, as well as the Doctor's numerous other flirtations with humans. Only Donna seems to have a problem with the whole 900-year-old alien thing. In the case of Time Lords, it's not the look that sets them apart from your traditional Star Trek type alien; The Doctor is centuries old and has seen and done so much that he's considered mysterious and alien by the standards of those who are mysterious and alien.
- Charmed did this right from the pilot. Between them the Halliwells have dated and in some cases married demons, half-demons, warlocks, angels, ghosts and god only knows what else.
Pheobe: ...which means I'm dating a warlock.
Paige: Been there, done that.
- Guardians of the Galaxy Vol. 2 gives us Ego and the many women he created offspring with, including Peter Quill's mom. His true form? You might know him as Ego the Living Planet. His human avatar is just that, a construct he uses to interact with other races.
- This also makes any romance Peter the half-Celestial has an instance of this.
- Fox maidens, usually malicious (Cunning Like a Fox) are common in Chinese, Japanese, and Korean mythology. Several examples are found in Strange Stories from a Chinese Studio ("Liao Zhai Zhi Yi") by Pu Songling.
- Rabbit maidens, such as the one in the Cantonese opera Tryst with a White Rabbit, are usually benign.
- Also celebrated is The Legend of the White Snake: a snake spirit falls in love with the student Xu-Xian. A Knight Templar type monk called Fa-Hai intervenes, not because she is evil, but simply because she is non-human. Fa-Hai's meddling did more harm than good.
- In South America there is the legend of the Encantados, pink river dolphins that change into men so they can seduce and/or abduct human women. Unexplained pregnancies? Hey, blame the dolphins. Who else could be responsible?
- Older Than Feudalism: Zeus in the Greek Myths, often changed into animals and seduced women. These relationships often produced children who were harassed or even killed by his wife, Hera. Helen of Troy — the most beautiful woman in the world — is likely half-swan, since that was the form Zeus took when he raped her mother. Some versions of her birth involve her hatching from an egg.
- Selkies? Swan-maidens?
- Human girls sometimes show interest in any incarnations of Ryu, the protagonist of the Breath of Fire series. The only thing is that his real form is a dragon.
- Makoto, one of the girls Yuuichi can fall in love with in Kanon is actually a fox.
- In Hanna Is Not a Boy's Name, Veser is the Half-Human Hybrid of a human and a selkie (see above). Going by the legend, though, she's not really a willing participant. Veser's Parental Substitute was also in love with her. It's a pretty dysfunctional family.
- In The Inexplicable Adventures of Bob!, Princess Voluptua spends most of her time looking like a very sexy woman, and the Unresolved Sexual Tension between her and Bob revolves around the fact that she's actually an absurdly long-lived giant alien insect.
- The Last Unicorn is fully sentient in her original form, so it may not fully count. But in a poignant scene there's still a slight moment of squick/hilarity when Lir, who's in love with her as a human finds out who she really is and says "Unicorn, mermaid, sorceress, no name you could give her would surprise or frighten me. I love whom I love." Schmendrick says "Well, that's a very nice sentiment, but when I turn her back into her proper shape..." and Lir just repeats stonily: "I LOVE WHOM I LOVE."
- Adventure Time: Finn is the only for-sure human in the world at the moment and lusted after by a whole harem of weird princesses. However, the only ones for whom serious romantic interest has been brought up are Bubblegum (a candy person), Marceline (a half-demon vampire), and Flame Princess (a fire person).
- Similar to The Last Unicorn example above, My Little Pony: Equestria Girls has Twilight Sparkle ending up with a crush on a human named Flash Sentry after she goes through a magic mirror and ends up in an Alternate Universe where all the characters are human. (Yes, she takes on human form, but she'd had it for less than a day when she fell in Love at First Sight with what should've looked like a Starfish Alien by her standards. Alas, he never finds out that he's crushing on a talking horse. Interestingly, there's a pony version of Flash Sentry, but there's barely any interaction between them (most notably, she takes zero notice of him before she's met his human counterpart, meaning that one moment of taking notice of him came from his reminding her of the human version!)
- In-universe, the Steven Universe episode "Open Book" has a fantasy book series that ends with the human protagonist's bird familiar turning human and marrying her. Connie finds this a pretty baffling case of Strangled by the Red String, but Steven actually saw them as having romantic tension even before the transformation.
- While it remains a point of contention within the scientific community whether archaic humans such as Neanderthals and Denisovans should be considered subspecies of Homo sapiens or different species altogether, there are definite physiological differences between us to the point of it nearing the Uncanny Valley. In spite of this, one of the several reasons for their extinction is that they were partially assimilated into our genome through crossbreeding, with Europeans and Asians carrying around 2% Neanderthal DNA on average.