'''''Animal X''''' is a lengthy {{yaoi}} manga by mangaka Sugimoto Ami.

Yuuji Ayukawa is a meek 27-year-old man who has never been in control of his own life. From his fiancée lecturing him about his shyness and sensitivity to his position as glorified guinea pig at Endou Chemical, Yuuji is the quintessential ExtremeDoormat.

One evening, he comes home to find that he has left a window in his room open. A wild young man who has just escaped government custody leaps out from beneath his bed and threatens to kill him. Yuuji's roommate, another in the long line of bullies Yuuji apologetically endures, bursts in...and is promptly decapitated by a fifteen-foot-tall T-rex. It turns out that Minato is a 17-year-old dinosauroid, part of a species that has long lived apart but parallel with humans, and he is capable of transforming into a reptilian killing machine under stress. ''Something'' has attracted him to Yuuji's room: Yuuji "smells like kin" and Minato is immediately overcome by an overwhelming desire to mate. From there, the story becomes the tale of various [[AncientConspiracy ancient conspiracies]], [[CorruptCorporateExecutive corrupt researchers and executives]], and Yuuji and Minato's evolving relationship.

And then [[MisterSeahorse Yuuji gets pregnant]].

It is probably one of the least sensational uses of [[GenderBender gender bending]] and {{Mpreg}} since ''[[UrsulaKLeGuin The Left Hand of Darkness]]''.

[[NamesTheSame Not to be confused with]] the DiscoveryChannel series about cryptozoological animals.

!!Provides Examples Of:

* AdultFear: [[spoiler:Yui's kidnapping]] is this to Yuuji and Minato.
* AnArmAndALeg: [[spoiler:Minato]] loses an arm and [[EyeScream an eye]] during the fight with [[spoiler:Maya]].
* ArrangedMarriage: Yuuji and Kyouko [[spoiler:(though it ultimately doesn't happen)]].
* {{Bishounen}}: Minato and Yuuji.
* BodyHorror:
** Yuuji takes manifesting female reproductive organs pretty well, but is scared of the idea of carrying a child to term.
** Later, he becomes detached and apathetic about his body as a coping mechanism for traumatic experiences. It's metaphysical BodyHorror.
* BreakTheCutie: Between MorningSickness, anemia, constant [[EvenTheGuysWantHim Even The Guys Want To Violently Violate Him]], having to bear the child of the man who raped him [[spoiler:(''twice'', after his gang rape by Shen and the other men of his village is revealed to have resulted in a pregnancy)]], and both him and his family being pawns/targets in half a dozen gambits, Yuuji cannot catch a break.
** He crosses the DespairEventHorizon when he finds out [[spoiler:what happened to his first child: she was subjected to vivisection, died, and then her remains were kept on ice in a research facility]]. After that, Yuuji is quietly broken and makes remarks that show that he's reached a point where he doesn't much care if he lives or dies. He eventually comes out of his depressed state, but is left deeply traumatized by the whole thing.
* ChildByRape: [[spoiler:Yuuji's first child]] was this. And so is [[spoiler:his third, yet unborn child of still uncertain paternity]].
* CuteLittleFangs: Minato. And how!
* DeusAngstMachina: By the tenth or fifteenth volume you'd be forgiven for thinking that the ''entire world'' has it in for Yuuji and Minato.
* DoubleStandardRapeMaleOnMale: {{Averted}}.
* DyingRace: Minato's.
* {{Hermaphrodite}}: Yuuji. "It feels like you're equipped for both."
* JumpingTheGenderBarrier: Yuuji and Minato are a good match, but Yuuji doesn't fall for Minato until after his transformation. He wonders if part of his heart has "become female too". See also TheMindIsThePlayThingOfTheBody.
* MarsNeedsWomen: Or, well, secret race of dinosaur people needs hermaphroditic hybrid.
* MateOrDie: Minato is hellbent on propagating his DyingRace.
* TheMindIsThePlaythingOfTheBody: Yuuji eventually makes references to thoughts that he, at least, identifies as coming from his male or female halves.
* MisterSeahorse: Yuuji [[spoiler:(for a total of three times now)]].
* [[NinjaPirateZombieRobot Ninja Pirate Zombie Robots]]: Police officers revived to hunt rogue dinosauroids. A (technically) zombie SWAT team. Yes. Even here, however, the series never breaks from its serious, thoughtful tone.
* NoPeriodsPeriod: Averted, naturally. Yuuji is...fully functional.
* PregnantBadass: A rare male example. Whether it's hormones or his newfound relationship with Minato, Yuuji becomes much more courageous, to the point of fully intending to take on a [[TyrannosaurusRex T-rex]] with nothing but a chainsaw.
* ShownTheirWork: Drumheller is a real town in Alberta, Canada, that claims to be 'The Dinosaur Capital of the World'. Even the landscapes are fairly accurate.
* WorthyOpponent: [[spoiler:Maya]] considers [[spoiler:Minato]] as this.
* YankTheDogsChain: [[spoiler:Not even a full chapter after rescuing Yui from her captors, Minato and Yuuji are told that 10 dinosauroid prisoners will be killed if they don't give her back. Minato grudgingly agrees that it's for the greater good, Yuuji adamantly refuses. He gets overruled.]]
* YaoiGuys: Yuuji and Minato, although Yuuji's biological reality raise the question of whether the series is, strictly speaking, "yaoi".
** Minato initially identifies Yuuji as a female (by scent) but refers to him with masculine pronouns. And though Yuuji has always been somewhat "feminine" (cooking, sewing, submissive, etc, forgive the generalizations) and [[{{Bishounen}} is very pretty]], he has lived his life and thinks of himself as a male. It's yaoi.
*** On the one hand, he always distinguishes himself from women, on the other, he doesn't consider himself and Minato to be a gay couple. "Ah, no, if that were so then we couldn't have children, could we?"
* [[YouWouldntLikeMeWhenImAngry You Wouldn't Like Me When I'm Angry]]: The dinosauroids turn into... well...''dinosaurs'' when stressed or angry, and not the sissy herbivore kind.