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Manga / Parasyte

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Parasyte (Japanese: 寄生獣, Kiseijuu) is a Science Fiction seinen manga by Hitoshi Iwaaki. It ran from 1988 to 1995 and is particularly famous for its usage of Body Horror. It's kind of like Devilman meets The Thing (1982) if directed by David Cronenberg.

One night, strange spores fall from the sky onto the earth. Out of them hatch weird little worms that quickly infiltrate human neighborhoods, looking for host bodies. The worms crawl or burrow their way into the head of a human host, transforming it and the brain inside. This effectively kills the victim, replacing the host's personality and intellect with that of the parasite. These parasites have a ravenous appetite for the flesh of the species they take over—in this case, humans.

But one specific worm goofs it up - he tries and fails to take over the brain of a teenage boy named Shinichi Izumi, but instead ends up stuck inside Shinichi's right arm. Because of this unique situation, Shinichi and the parasite, who eventually names himself Migi (meaning "right") are sharing the same body, but still possess their own individual intellects. This gives them an edge in battling the other parasites, who see Shinichi's ability to think independently as a threat. Shinichi also feels compelled to fight other parasites, who kill and eat humans as a source of food, in order to protect humanity; Migi on the other hand, like most other parasites, is incapable of emotion and only fights to preserve his and Shinichi's lives. Thus, Shinichi is forced to deal with all kinds of teenage issues while keeping a horrifying secret and having to battle against hordes of enemies who want to use him or kill him.

Parasyte was first published in North America by Mixx (now better known as Tokyopop), which Americanized every character by changing their names (Reiko Tamura was renamed Tamara Rockford, while Migi was "Lefty" because the pages were reversed, for example), censored some sexual elements (though the graphic violence was left untouched), and did away with many Japanese cultural signifiers in the story. Publishing rights were later obtained by Del Rey, who re-released it, reverting the changes Mixx made and using a more accurate translation, as well as compiling the chapters into a more compressed format, changing it from 12 volumes to only 8.

A 24-episode anime adaptation by Madhouse titled Parasyte -the maxim- (Japanese: 寄生獣 セイの格率, Kiseijū Sei no Kakuritsu) aired from October 9, 2014 to March 26, 2015. The anime modernizes the manga, using the same premise and main cast but also integrating things that were not commonplace during the manga's original run, like smartphones and the internet.

The manga was also adapted into two live-action films in Japan in 2014 and 2015. The films also modernize the setting and are more condensed compared to the anime. A Korean live-action drama version, known as Parasyte: The Grey, is schedule to stream via Netflix in second quarter 2024.

Two collections of short stories set in the world of Parasyte, Neo Parasyte f and Neo Parasyte m, were published in 2016 and 2017. These stories occur during and after the events of Parasyte, showing what became of Shinichi, Satomi, Migi and the parasites. A spinoff, Parasyte Reversi, was published with 8 volumes by Moare Ohta. It center on Tatsuki Hirokawa, the only child of East Fukuyama mayor Takeshi Hirokawa, as he tries to investigate whether his father has secret links with parasites after some of his classmates were murdered by them. Storywise, it takes place simulateneously with the original manga.

Sentai Filmworks has announced home video license and distribution for the anime in five territories (North America, South America, United Kingdom, Australia, and New Zealand). Parasyte is one of the most requested titles to air on [adult swim] Toonami (even long before Sentai Filmworks made their announcement for home video rights), and eventually aired on the block beginning in October 2015.

Tropes in this manga include:

  • Absurdly Sharp Blade:
  • Adaptation Title Change: The anime adaptation was titled Parasyte -the maxim-.
  • Armor-Piercing Question: The manga is filled with these. The moral and ethical standards we humans built for ourselves are put to question when a third party enters our paradigm as a mirror to our inhumanity and savagery.
    Migi: Parasites can change their appearance easily. Humans won't be able to catch them.
    Shinichi: That's why we will chase them down—
    Migi: And kill them?
    Migi: Shinichi! I don't have human feelings. I don't feel anything when I kill my own species. But what about you? Will you be able to kill them?
  • An Arm and a Leg: Shinichi loses his right arm when Migi seemingly sacrifices himself to stop Goto from killing them both, but he gets better.
  • Arc Words: "Are you really Izumi-kun?" Satomi asks this when Shinichi starts acting strangely. At first, it's a joke, but it becomes an increasingly real question over the course of the series, as Shinichi's secret struggle to survive changes him mentally and physically.
  • Asteroids Monster: The Shapeshifting Blob Monsteresque parasites can separate into fairly small fragments.
  • Ax-Crazy: Uragami, who is shown remembering how he got captured, which includes visuals of some of his victims, one of whom he raped after he decapitated her.
  • Badass Bookworm:
    • Migi spends a lot of time reading and studying when Shinichi is relaxing in his bedroom.
    • Shinichi averts this due to having to spend so much time fighting or fleeing from the parasites and it comes back to bite him big time; see Bittersweet Ending.
  • Bad Powers, Good People: Shinichi is one of the kindest people in the entire series, but he has a Lovecraftian Superpower and has to share his body with a sapient creature with Blue-and-Orange Morality.
  • Bare-Handed Blade Block: The first time that Migi speaks to him, Shinichi tries to stab the thing with a kitchen knife. Migi catches the point by clapping it between two of his miniature hands, and uses a third appendage to slice the blade in half.
  • Battle Amongst the Flames: The climatic battle takes place in a nuclear waste incinerator in the movie adaptation.
  • Be Careful What You Wish For: Early on, Shinichi wishes that Migi would fall asleep forever, and when he finally seems to in the end, Shinichi is devastated.
  • Betty and Veronica: Shinichi gets into something of a Love Triangle with his current girlfriend, Satomi Murano (Betty), and the rebellious girl Kana (Veronica). Kanna sadly ends up dying, and Shinichi ends up with Murano for the long term.
  • Big "NO!": Shinichi has one when Uragami is about to cut Satomi's throat, and again when she's falling from a building.
  • Bio-Augmentation: Shinichi gains superhuman powers after Migi heals his heart using his own blood.
  • Bittersweet Ending:
    • The parasites' organization is broken, Hirokawa and Goto are dead, and parasite violence is almost nonexistent. Once again without a "natural predator", it's left unclear if humanity will render Earth completely uninhabitable one day.
    • Shinichi and Satomi are happily together, and she's now in college; however, because of all the school he missed while fighting the parasites, Shinichi didn't go to college at the same time as Murano, and will take another year to catch up with her (but she agrees to help him study for the entrance test.) Tamura is dead, but she ultimately sacrificed her life to save her baby, which allowed Shinichi to feel emotions again. Detective Hirama assures Shinichi that if the boy is fully human, he will see that the baby is adopted by a loving family, and since Tamura assured Shinichi that he was, it's safe to assume that Tamura's last wish, that he be taken in by good humans and raised well, is coming true..
  • Blood Knight: After the battle in volume seven, Goto drops the civilized act and claims that he's a wild animal who only lives to fight.
  • Blue-and-Orange Morality:
    • Parasites eat humans because that's how they survive as a species, and they feel no more guilt about killing the sapient lifeforms who serve as their prey than humans do about eating livestock such as pigs and cows. Most are either incapable of emotion or don't care enough about it to try, so whenever they explain the reasons behind their actions, it's very matter-of-fact. Furthermore, each individual of the species will do anything to ensure its own survival. Migi is frequently baffled by what he sees as Shinichi's irrational human behavior and thoughts, and considers Shinichi's objection to plans he suggests—such as using his classmates as human shields in order to defeat A, or even just pickpocketing money to purchase a cab ride to safety—to be a misguided case of Honor Before Reason.
    • Shinichi very briefly goes into Blue and Orange insanity when he decides that humans have no right to kill an organism just because it's harmful to humans and no right to impose human values on parasites. He changes his mind after coming to the conclusion that all he can do is act as a human and protect humans, though at this point in his Character Development, he pities Goto more than hates him, and finally reluctantly finishes him off.
  • Body Horror: To put it mildly, it's the page image on the trope page for a reason.
  • But Now I Must Go: Migi decides to fall asleep permanently at the end of the series, but wakes up suddenly and silently after Murano is pushed off the roof of the building Shinichi is on to grab her just in the nick of time.
  • Cannibal Larder: Horribly mangled body parts are found all over the world. Unusual in that the culprits are not cannibalistic humans, but alien bodysnatchers who eat people as a source for food.
  • Car Fu: During Goto's pursuit of Shinichi, Migi drives a car off a mountain road to land on Goto's car further down the mountain. It doesn't work.
  • Catch and Return: During the military's move against the parasites, Goto catches the 16.8mm buckshot they're shooting in his parasite flesh, and then massacres everyone in the room by launching them back.
  • Caught with Your Pants Down: Played With. When Migi tries to stimulate Shinichi's erection, it is Shinichi's right hand that's doing it, but he's not necessarily masturbating but it becomes an assumed excuse for a situation where Shinichi's mother barges into his room without knocking and he has to hide Migi.
  • Central Theme: What makes a human a human, and what makes a monster a monster? Can a human become a monster, and can a monster become human?
  • Chekhov's Gunman:
    • So, you remember Uragami, the Serial Killer the police brought in to help identify parasites? The one who escaped and disappeared during the big police raid after shooting his handler? He comes back in the last chapter.
    • Earlier in the story when Migi met another parasite that had succeeded in possessing its host, it mentions that Migi should move off of Shinichi's body and into his right hand. Migi wonders if it's really possible. The Big Bad Goto turns out to be a mass of parasites in a body, with two capable of controlling them all as the head.
    • When Goto escapes from city hall, he is shown to have two bullet wounds where Yamagishi and his troops shot him. In the final volume, hoping it's the tiny chink in the armor he's been looking on, Shinichi stabs him there with a metal rod — the rod was covered with poisonous pollutants, leading to Goto's defeat.
  • Chick Magnet: Shinichi is depicted as one. His crush Murano obviously likes him. On a trip, he meets a girl on a boat who, later on, keeps following him around and seems to be interested in him. Kana also develops a crush on him after sensing that he's not totally human and begins to keep an eye out for him wherever she goes with the help of her special powers, which allow her to sense whenever he's nearby. She also dreams about him in a sort of white knight scenario in which he saves her from monsters and they embrace; she remembers this dream as she dies and chuckles, remarking that it's too embarrassing to talk about.
  • The Chikan: Tamura is introduced dealing with one on a subway ride and tossing him off the train at a stop. He unwisely attempts to ambush her later to get revenge for publicly humiliating him, so she kills him.
  • Chucking Chalk: Shinichi's teacher does this twice to him early on. The first time, Migi instinctively catches and crushes it without Shinichi even noticing, much to everyone's amazement; the second time, the chalk hits him because Migi had fallen asleep.
  • Combat Tentacles: Parasites fight by twisting into long whiplike stalks with razor-sharp blades on the end.
  • Composite Character: In the live-action adaptation, the parasite known as "A" survives his first fight with Shinichi and Migi so he can take the role of the nameless parasite who killed Shinichi's mother and took over her body.
  • Contrived Coincidence: Shinichi's parents just so happen to be on vacation in the immediate vicinity of a parasite who, thanks to a series of accidents, needs a new body. The result is that Shinichi's mother is beheaded so her body can be taken over.
  • Cool Old Lady: Mitsuyo. She takes Shinichi in after his fight with Goto, loudly defends him from the suspicious neighbors, drinks with him, and gives him some parting words of wisdom as he leaves to finish Goto off.
  • Crazy Enough to Work: Invoked. When Migi and Shinichi split up to fight Goto, Migi pretty much thinks, "This is an extremely reckless strategy, but that means Goto is unlikely to anticipate it."
  • Creepy Monotone: How all the parasites talk (except for Uda's, who he named Jaw — he learned to talk by watching TV, so he speaks animatedly and uses slang). When a human starts speaking this way, it's a tipoff that they've been taken over.
  • Crippling Overspecialization: The parasite who killed Shinichi's mother always goes for a One-Hit Kill by stabbing its enemies in the heart. When Uda's parasite Jaw realizes this, he's quick to protect Uda's heart in anticipation and behead the enemy parasite from behind.
  • Death Glare: Being host to Migi gives Shinichi the ability to unleash awesomely powerful glares, representative of people being able to sense how deadly the pair of them are (the manga supposes that animals are able to instinctively tell when another animal is more powerful than them, and Shinichi and Migi are FAR deadlier than any human).
  • Deliver Us from Evil: After giving birth, Tamura starts to take on increasingly human traits, eventually becoming driven to protect her child at any cost, even when it means laying down her life.
  • Diagonal Cut: A parasite's organic Absurdly Sharp Blade can cut through a human so quickly and cleanly that they'll have time to get scared before they realize they're already dead.
    • In Chapter 3, a parasite performs a three hundred sixty degree Clean Cut all around him, remininiscent of a helicopter blade, which causes the humans in front of him to fall to pieces right away, but the woman behind him is seemingly left standing. She raises her hands to her head and screams, only for her head and hands to belatedly separate from the rest of her.
    • In Chapter 6, Tamaya kills The Chikan who came back to get revenge on her for calling him out with a single cut. At first his hand comes off and the sight of it makes him freak out, then he turns his head to see the wound opening in his neck, and as his head falls off his eyes are transfixed on the bleeding stump of his neck, as if he can't believe what hit him.
  • Discard and Draw: In a successful effort by Migi to save Shinichi's life, Migi sacrifices part of himself by traveling inside his body and patching up his heart; as a result, he now has to go into hibernation for a few hours each day, during which time he cannot wake up at all, which means he can't fight or use his parasite detection sense to help Shinichi. On the plus side, this incident left Shinichi with superhuman physical capabilities at all times.
  • Does This Remind You of Anything?: How did Shinichi stop Migi from reaching his brain? By tying his earphones' wires into a tourniquet around his own arm. Lampshaded — his parents walk in soon after to see the aftermath and ask if he's using drugs.
  • Double-Meaning Title: Parasyte is titled 寄生獣 (Kiseijū) in the original Japanese, literally meaning "Parasitic Beasts". On the face of it, this refers to the Puppeteer Parasite alien species which appears among humanity and begins to prey on humans. At the same time, however, it refers to the theme of humans being a threat to themselves and the earth through overpopulation and environmental destruction. Toward the end, the leader of the parasite conspiracy, Takeshi Hirokawa, accuses humanity of being the real parasites by destroying the Earth, performing a Title Drop by calling humans "parasitic beasts". However, the author states in the interview that humans' being parasites is Takeshi's opinion, not his; in fact, the author goes on to mention that perhaps all living beings on the Earth can be considered parasites from the Earth's POV, implying that the title isn't referring to one organism in particular.
  • Earn Your Happy Ending: Shinichi goes through hell and back and is forced to witness several brutal, traumatizing deaths, but in the end the parasites have pretty much stopped killing humans, and he finally gets to be with Murano.
  • Evil Hand: Subverted; Migi has pretty much no moral compass and is only concerned with protecting himself and Shinichi, but isn't really evil, just focused on self-preservation to the point that he'll encourage Shinichi to let innocent people die for their advantage or try to kill someone if they discover his existence.
  • Expository Hairstyle Change: Shinichi has one after he and Uda take down the parasite who killed his mother.
  • Faking the Dead: That's how Jaw manages to survive the attack from Shinichi's mother parasite. After realizing that his opponent was going for a One-Hit Kill by trying solely to pierce Uda's heart, Jaw changed the locations of Uda's organs and let him be hit. Afterwards, he just needed to wait for the perfect occasion to do a sneak attack — his plan worked without a hitch, and the parasite was killed.
  • Fan Disservice: Panty Shot on a woman chopped in half. Later there's a necrophiliac and a humanitarian moment — at the same time. And then there's also the scene of Uragami polishing his rocket when seeing a pretty girl.
  • Feel No Pain: The parasites are connected to the host body's nervous system so they can sense injuries and negative stimuli, but they have no psychological or physiological attachment to the discomfort they feel. As such, they can't be psychologically distressed by any sensations from injuries, nor can these sensations affect them physiologically (a large amount of pain can do all kinds of nasty things to a person like shut them down entirely). This becomes evident when Yamagishi blasts away a parasite's hand; he doesn't so much as blink.
  • Five-Finger Fillet: When Shinichi first tries to confirm whether his right hand has been taken over by an alien, he places his palm on the table and prepares to stab a knife between his fingers, reasoning that it will dodge of its own volition if it isn't his.
  • For the Evulz: Not the parasites, but the human Uragami kills and rapes for no other reason than because he wants to.
  • Gag Penis: After discussing with Shinichi regarding his attraction to Satomi, Migi shapeshifts into a giant erection while the two are at a restaurant. She doesn't notice.
  • Gaia's Vengeance: Reiko Tamura (at least in the beginning) and the totally human Takeshi Hirokawa believe the parasites were created to cull the human population to preserve the earth.
  • Good Eyes, Evil Eyes: A good way to tell who's a parasite is by their emotionless gaze. Subverted a few times - some humans have the same look in their eyes as the parasites do. There's also Miki, a parasite who learned how to look and act genuinely human.
  • Gory Discretion Shot: Used exactly once: Shinichi's mother's death occurs offscreen and her injuries are never shown, unlike other offscreen deaths.
  • Green Aesop: Actually subverted towards the end. Shinichi comes to the realization that no matter how much humans want to empathize with other creatures and understand nature, at the end of the day they're just humans and can only live as humans, for better or worse.
    You can't care about the planet without caring about mankind as well.
  • Half-Human Hybrid: Shinichi becomes one when Migi uses some of his body mass to repair the stab wound caused by the parasite that took over Shinichi's mother. This results in advanced strength and reflexes, and also in Shinichi seemingly becoming more emotionless for a time.
  • Handicapped Badass: While separated from Migi and thus having a stump for his right arm, Shinichi manages to catch six mosquitoes in less than a second.
  • Heroic Host: Shinichi and Uda, whose parasites weren't able were take over their brain and were thus confined to other parts of their bodies.
  • Heroic Sacrifice: Migi, in a very touching scene
  • Hope Spot: Migi finally agrees to allow Shinichi to let Kana in on the loop about the nature of Parasites. She dies before he's ever able to do so.
  • Horror Hunger:
    • Every parasite is driven to eat humans by nature, even though Tamiya Ryoko proves that they can survive by eating the same way humans do.
      Tamiya: “Flies know how to fly without being taught. Spiders know how to spin webs without being taught. Why is that? Here’s what I think: Flies and spiders are simply following an order. I believe all lives on Earth have received orders of some kind. Don’t humans have any directive? When I took over this human’s brain, I received a directive. It said, 'Devour this species.'"
    • Migi and Jaw are the sole known exceptions of their species as they never took over a human brain nor do they need to eat; they get all the nutrition they need directly from their hosts' bloodstreams.
  • Horseback Heroism: Shinichi in Kana's dream.
  • Humanity Is Infectious: Ultimately the case with Tamura; she comes to care about her baby boy and even sacrifices her life to keep him safe.
  • Humans Are Flawed: Going hand-in-hand with the subverted Green Aesop, this is Shinichi's view at the end, but he concludes that our flaws do not make us necessarily bad.
  • Humans Are the Real Monsters: Some of the more socially-conscious parasites at least believe this is the case.
  • Impostor-Exposing Test: The military figures out a way to use an x-ray machine to detect parasites among humans. Before that a simpler method was devised in which you pluck a hair off the person's head — in the case of a parasite, the ambulatory but non-sentient cells would writhe and shrink before dying.
  • It Can Think: The first few parasites seen are slow-witted and relatively dumb, but as the story goes on, the parasites quickly display the ability to learn and adapt to their circumstances, not to mention prioritize their actions. This is particularly the case with Tamura, whose scientific bent allows her to anaylze situations and perform experiments such as Goto, and even sacrifice other parasites to ensure her own safety and well-being.
  • It's Personal:
    • When a parasite kills and takes over Shinichi's mother, Shinichi becomes hellbent on taking it down.
    • Averted when Shinichi's beaten Goto, and the pieces of his body are trying desperately to reunite, which Migi estimates only has a 50% chance of succeeding. At this point in his character development Shinichi has developed empathy towards the parasites and makes it clear that it's Nothing Personal before finishing him off, thereby also nicely averting Once is Not Enough because he makes sure that he's dead.
  • Killing Intent: Comes up a few times; after Migi spreads some of his body into Shinichi's heart's stab wound to save his life, he gains the ability (although it doesn't seem like he's always aware that he's doing it) to give someone a terrifying Death Glare that instantly scares the hell out of them, if not causes them to turn tail and bolt. Parasites themselves can also send out a powerful killing intent that animals can sense keenly; birds with suddenly fly away, and even a lion is intimidated.
  • Kill It with Fire: Strangely averted here, as practically everything else gets used — dismemberment, impaling, gunfire from bullets to shotguns, and on one occasion, a rock. Flamethrowers are briefly considered, but rejected. After Goto has proven nigh-invulnerable to the weapons that Yamagishi and his troops had been using to great effect against other parasites, Yamagishi's last thoughts are that maybe a flamethrower would have done the trick. The one time it's used (Shinichi's plan to hit Goto with a flaming spear while Migi takes off his head) it fails.
  • Lack of Empathy:
    • All of the parasites are supposedly completely incapable of emotion. Migi and Tamura eventually get a little better about it.
    • Shinichi finds himself incapable of crying for a while as Migi's influence on his body grows, eventually getting over it when Tamura gives him her baby.
  • Last Stand: The battle at city hall is this for Hirokawa's parasites. Ironically, Yamagishi and his troops — the men who eliminated the aforementioned parasites — end up in a last stand of their own against Goto.
  • Lighter and Softer: Has a one-shot crossover with Fairy Tail where Migi is less terrifying and there's a lot less blood.
  • A Lighter Shade of Black: While the parasites are ruthless killers (some of whom want to take over humanity) they're definitely much better in comparison to Uragami. In fact, some of the parasites even develop human emotions over the course of the series.
  • Losing Your Head: Shinichi cuts off Goto's head in their first fight. Goto doesn't care.
  • Lovecraftian Superpower: Migi, a parasitic blob of cells in the form of Shinichi's right arm, gives him shapeshifting, super-strength and speed, and supreme emotional control.
  • Mama Bear: Tamura of all people managed to pull this on Kuramori when he made a move like he was about to drop her baby off a cliff; after she stabs him, he says he's surprised that she actually cared enough about her son to act, and she says that she's surprised too. She takes it as far as possible when she cradles her son to her chest and shapeshifts to shield him from harm when the cops get there and begin to collectively fire on her; she simply takes the bullets unmovingly to avoid the chance that her son might be hit, and before she dies, she hands him off to Shinichi and asks that he find a good human family to take care of him. Once he agrees, she peacefully dies with a smile on her face.
  • Masquerade: The parasites try to maintain one, but it breaks down very early. The government, meanwhile, is less about "masquerade" and more about "information control," releasing information to the public as needed to avert panic.
  • Masturbation Means Sexual Frustration: While screening people for parasites, Uragami gets turned on by an attractive woman brought in front of him and starts masturbating to her. This freaks the woman out and leads her to believe he has a parasite.
  • More Dakka: About ten men shoot Goto with assault rifles, shotguns and a grenade launcher at the same time. He doesn't care. See also Catch and Return.
  • Mugging the Monster:
    • A bully and rival for Murano's affections tries to beat up Shinichi. Shinichi tries to avoid the fight at first, but the bully is having none of that. It doesn't end well.
    • Also Mitsuo, another bully and Kana's ex-boyfriend. After Kana dumps him, he tries to beat up Shinichi again in revenge. It ends about as well as one would expect.
    • There is another time when Mitsuo tries to take on Shimada, the time when Yano is shown to be the real leader. Subverted when the leader knows very well that he is outmatched and walks away when he has the chance.
  • My Sensors Indicate You Want to Tap That: Migi to Shinchi about Murano. He even shapeshifts into a gargantuan penis.
  • Neck Snap: Manga-only, Miki snaps the neck of a girl he was dating, and is caught red handed by Abe. Miki proceeds to do the same to Abe. The act itself is not shown in the anime, only the girl's corpse.
  • Nice Job Fixing It, Villain: At first Kuramori refuses to help Shinichi fight the parasites out of fear for his family. However, the parasites associated with Tamura decide to eliminate him because of his knowledge. The attempt fails, with Kuramori's wife and daughter ending up murdered, turning Kuramori into a grieving, vengeful father and widower with nothing left to lose. Tamura chews out the parasites responsible.
  • Nigh-Invulnerability: Goto. Since he's five parasites in one body, all his limbs are tough and lack human weaknesses, and he has enough cell-mass to armor over his torso as well.
  • Not Me This Time: Uragami was caught by the police when they stumbled upon him at the scene of a parasite meal; he doesn't deny that he's the serial killer they've been looking for, but he does loudly object to their idea that he's the culprit of this particular killing.
  • Off with His Head!: Parasites tend to go for the head, whether they're infecting or just feeding.
  • Oh, Crap!: The parasite who took over Shinichi's mother's body has several during its fight against Shinichi, who is able to follow and dodge its movements.
  • Paper-Thin Disguise: Uda's parasite gives him a ridiculous, inhuman jawline when he and Shinichi have to kidnap Kuramori.
  • Paranoia Fuel: The police's efforts to avert full-scale public panic should the parasites' existence become known are a recurring plot point.
  • Parasites Are Evil: Plays with this trope extensively:
    • The titular parasites may be sapient creatures who see their human hosts as nothing more than livestock to kill, devour, and impersonate, but they're not always chaotic evil for it, nor are they treated as such by the story. Instead, they operate under Blue-and-Orange Morality; at best they're logical, ruthlessly pragmatic beings who only do what they do because they believe it's how they survive. Some even learn human emotions and empathy over time. In fact, the majority of outright evil characters are a handful of ordinary humans.
    • Shinichi, the protagonist of the series, even goes as far as to call this trope into question, deciding towards the end that humans have no right to hold other species to their values. Though adjusts his view quickly to clarify that he does still have to put Goto down, he still lets go of any malice against the parasites.
  • Parasite Zombie: The parasites infest a host's brain and proceed to Kill and Replace them. They're not obviously nonhuman unless they're feeding or fighting, in which case their heads turn into Combat Tentacles and mouths with More Teeth than the Osmond Family.
  • Playing Possum: Jaw made Shinichi's mother's parasite think it was dead and waited before finishing it off from a sneak attack from behind when it was distracted.
  • Police Are Useless: Played straight early on, when the cops are just as clueless about what's going on as the rest of the country. By the end of the series, however, they've learned all about parasites, classified them as public enemy number one, come up with methods to differentiate them from humans, and developed tactics to kill them.
  • Power Perversion Potential: Averted; Migi's ability to turn Shinichi's hand into a giant penis or mass of writhing tentacles never comes up, since he isn't out to make either of their lives harder.
  • Precision F-Strike: A grand total of one in the anime, dropped by Migi of all people. Serves the double purpose of showcasing Migi's Character Development and how scared he is of the coming fight with Goto.
  • Primal Fear: Shinichi can cause people to experience this by delivering a bone-chilling Death Glare, especially when he's being threatened. It's unclear as to whether or not he's always conscious that he's even doing it.
  • Product Placement: Unintentional, but the appearance of an undisguised McDonald's in chapter 2 is a fairly rare sighting in manga.
  • The Quisling: The mayor was Human All Along.
  • Radiograph of Doom: A large x-ray is used by the military to spot the parasites in volume seven.
  • Removing the Head or Destroying the Brain: Subverted — taking the head clean off should kill a parasite, but they can regenerate from most partial injuries. Going for the vital organs tends to work better.
  • Repeat Cut: When Hideo is hit by the rock thrown by Shinichi.
  • Revival: In 2014, as both an anime and Live-Action Adaptation after over 20 years!
  • Riddle for the Ages: It's never revealed what exactly the parasites are or where they came from.
  • Rōnin: Shinichi fails the university entrance exams due to missing so much school, and has to study and catch up in the epilogue. Fortunately, Muraro is there to help.
  • Rule of Symbolism: Tamura holding her baby close to her chest and shielding him from bullets while the cops are shooting her to death is reminiscent of a certain virgin....
  • Scars are Forever: Shinichi picks up large scars on his chest and back as a result of Migi saving his life, and a scar through his right eyebrow thanks to Goto.
  • Sex Signals Death: Shimada baits a fat girl to follow him to an empty alley, where he eats her alive. The fact that the girl is seen completely naked when Shimada brutalizes her (while he is topless) means she was probably fooled into believing she was getting laid.
  • Shapeshifter Weapon: Parasites can transform the parts of their hosts' bodies that they've taken over (usually just the head) into blades that can shred human flesh faster than the eye can see.
  • Shotguns Are Just Better: The task force commander figures out very quickly that a shotgun blast to the heart will kill a parasite near-instantly. A load of buckshot is also much harder for them to deflect than slugs fired individually.
  • Shout-Out:
    • The premise traces back to Devilman, an influential manga with another initially shy protagonist who merges against his will with a being with Lovecraftian Superpowers and is put to fight other similar beings that are instead taking over their hosts. His love interest is even surnamed Makimura, just like in this case the surname is Murano.
    • The parasites' body distortion seems to be inspired by MC Escher's 'Bond Of Union', by way of John Carpenter's The Thing (1982).
    • The idea of a parasite taking over the government to some degree is most definitely inspired by They Live!.
  • Shut Up, Hannibal!: The soldiers don't wait to the end of Hirokawa's speech to shoot.
  • Surprise Jump: A nervous Shinichi is tugged at from behind by a young girl. Because of his newfound powers, he jumps a good 20 feet or so.
  • Surprisingly Realistic Outcome: After the rest of the series has had superhuman battles between the parasites, Uragami as a Post-Climax Confrontation makes a big show in targeting Shinichi and Murano — and then gets downed in a single good punch to the face that breaks his jaw. Even without Migi's powers, not only is Shinichi's body still at peak capability, but Uragami is a mere human that isn't experienced in a direct fight. He was way out of his league besides having a knife on-hand.
  • The Symbiote: The parasites can be categorized as either the parasite type (those that harm their hosts while also benefitting) or the mutualist type (those that co-exist with their hosts to mutual benefit). The parasites that take over humans are obviously the first and can also be parasitoids if they have to find new hosts (parasatoids are different from normal parasites in that they specifically end up killing hosts) which entails them lopping off the head and quickly taking the its place before the body dies. Migi and Jaw, who only take on a portion of the host's body, are mutualists that protect their hosts from harm while giving them enhanced abilities, and while they feed off their host's blood for nutrition, it only results in their hosts needing to take in more calories.
  • 10-Minute Retirement: Kuramori emphatically decides to opt out of further investigation after witnessing a parasite battle firsthand. He's just an ordinary human — he has a wife and child, and the whole thing is just not his fight. Little late for that. The parasite syndicate goes after him, but they flub it and kill his wife and child instead; this causes him to be thrown back into the conflict when the police question him to find out what happened.
  • Theme Naming: Migi (Japanese for right) and Jaw are named for the parts they're inhabiting in their respective hosts - the right hand and the jaw.
  • They Look Like Us Now: As time goes on, the parasites become more and more human, until finally there's no obvious physical differences between them and ordinary people.
  • Tin Man: Played with: the parasites all claim to have no emotions, but in truth it's actually more complicated. They generally lack empathy and are cold and expressionless, but some such as Goto seem to have something akin to bloodlust. As for human emotions, many feel them, just less strongly than humans; they apparently can (with time) develop complex personalities and emotions. This is evidenced by Tamura protecting her son with her life and Migi sacrificing himself for Shinichi's safety and internally thanking Shinchi for his friendship — he even says that he's glad he didn't succeed in taking over his brain.
  • Title Drop: When Hirokawa gives his final speech, calling humans "worms - or parasytes." In the original Japanese he calls them parasitic insects (kiseichuu) and corrects himself to parasitic beasts (kiseijuu AKA the Japanese kanji). In the Del Rey translation, this is one of only two places where the "Parasyte" spelling is actually used, the other being as a nickname for Uda's parasite before he settles on "Jaw".
  • Too Dumb to Live: Kana’s final fate. She ignores Shinichi's warning against trying to detect and follow him using her "power," since in her infatuation she's convinced herself that she'll be able to tell the difference between the aura of Shinichi and another parasite. It turns out she can't, and when she walks in on a hostile parasite instead of Shinichi it impales her through the body. Since she's a baseline human in all other aspects, she has lost too much blood to be saved by ANY means by the time Shinichi finds her.
  • Took a Level in Badass: After recovering from the stab wound that pierced his heart, Shinichi can run at what looks like more than thirty miles per hour, jump more than twelve feet high without a running start, develops Super-Hearing and Super-Reflexes that allow him to anticipate and dodge parasite attacks, which are faster than the human eye can see.
  • To Serve Man: The parasites have a desire to hunt and consume the species they take over, and their preferred hosts are humans (we do see one parasite who took over a dog eating another dog). The kicker is that they can actually survive perfectly well off of a non-human diet, but (most) parasites don't feel empathy and thus see no reason to change their lifestyles.
  • Unable to Cry: Shinichi finds himself unable to shed any tears after he is turned partly parasite by Migi, even when he witnesses the death of his mother's body or when Kana is killed by a parasite. He's finally able to cry again when he watches Tamura sacrifice her life for her son.
  • Uncanny Valley: In the story, parasites are generally indistinguishable from normal humans. However, they tend to have completely blank expressions, and the artwork often endows them with slightly overlarge and sharply-defined eyes that give them a sinister appearance. Extremely twisted humans such as Uragami also have these eyes.
  • The Unreveal: We never find out where the parasites really come from (aside from outer space) or why they have such an innate killing intent for their host species. Some individual parasites such as Tamura do ponder these things, but most don't really care since it doesn't impact their lives.
  • Visual Pun: Since parasites only feed on the same species they take over, the first parasite-dog is seen eating another dog. Which would make it literally a dog-eat-dog world out there.
  • Vomiting Cop: One of the two cops who catch Uragami at the scene of a parasite meal can't help but throw up upon seeing the body.
  • Wainscot Society: Hirokawa's group of parasites function a lot like a mafia. Hirokawa serves as the mundane mayor of a city and establishes feeding areas where dead humans can safely be disposed of. Their status as a society is cemented by having territorial rules, which also apply to Shinchi: When a parasite kills Kana at Shinichi's school and Shinichi kills him, they let it go because the guy was clearly a dangerous fuckup operating on turf they recognized as Shinichi's, but when Shinichi kills one of their own in the dining garage, it's an act of war and Tamura has to reluctantly give the go-ahead to wax him.
  • Weirdness Censor: It takes a while before people other than Shinichi realize that nonhumans creatures are among them, despite the fact that, on multiple occasions, the parasites shapeshift right in front of many witnesses (such as the incident when a pouncing lion is turned to mincemeat by a parasite, and witnesses desperately and fearfully concoct the explanation he somehow managed to hit the lion with an explosive weapon in mid-flight despite never moving his arms). The sudden massive spike in grisly murders around the world is initially believed to be the work of an international cult.
  • Wham Episode: Chapter 11 contains horrifying amounts of wham.
  • What Happened to the Mouse?:
    • Characters such as Mitsuo, Detective Hirama and Miki disappear from the story without mention.
    • Happens in-universe to all the parasites after the raid on City Hall — after their existence becomes public knowledge, virtually all attacks and sightings of them disappear. They realized that open attacks and attempts to organize against humanity is dangerous for their survival — most adjusted their diet to eat regular human food to accomodate. It's also possible that those small few who continued to kill adapted to disguise their feedings as more conventional murders.
  • What the Hell, Hero?: When Shinichi picks up a puppy in the middle of the road who was hit by a car, Migi determines that it would be dead within ten minutes. Shinichi goes to a quiet park and sits the puppy in his lap, petting it and giving it a good final few minutes. Murano finds him and they sit together in somber silence. Sure enough, the puppy finally dies, but the moment it's gone, he loses all sympathy — he even calls it "meat in the shape of a dog" and just throws it into the trash bin. Satomi angrily calls him out on his sick callousness and it makes him realize how much he's changed. He gives the puppy a proper burial afterward, but Murano isn't around to see.]]
  • Will They or Won't They?: Shinichi and Murano. They will.
  • The Worm That Walks: Goto is made of several parasites, each controlling a limb.
  • Xtreme Kool Letterz: Parasyte, Mixx's Market-Based Title for Kiseijuu; Mixx used it to refer to the parasytes; Del Rey used the normal spelling to refer to the creatures and instead implied that the titular "Parasyte" was humanity.
  • You Are Already Dead: Many humans hit by a parasite's blade don't realize they've already been decapitated or cut to pieces, which gives them enough time to scream before they fall apart.
  • Your Approval Fills Me with Shame: Shinichi really realizes he's not acting right when Migi tells him that his decreased empathy is normal for his species.

Further tropes in the anime include:

  • 2D Visuals, 3D Effects: The office workers when talked to in the lobby in episode 19 and 20.
  • Accent Adaptation: Mitsuyo is given a Southern Accent in the dub.
  • Ascended Extra: One of Shinichi's classmates, a girl with glasses named Yuko who briefly appears in the manga, appears as a friend of his in the first episode where she even has more lines than Murano. Her role is expanded more later in the anime.
  • Award-Bait Song: The ending theme, It's The Right Time by Daichi Miura.
  • Bowdlerise: While the anime has plenty of Body Horror and on-screen deaths, the manga is far more explicit with the gory scenes. If a violent scene is particularly gruesome, the anime either downplays it, uses Gory Discretion Shot, or flat out Censor Shadow.
    • Worth mentioning is that the anime rarely shows female characters getting gored by a parasyte (other than maybe the aftermath), while the manga does not shy away from doing that. The most glaring example being Shimada murdering a fat girl; It is shown with full detail in the manga, while the anime justs... sort of implies it.
  • Dubstep: Sometimes used for action scenes.
  • Early-Bird Cameo: The first episode of the anime shows Uragami long before his first appearance in the manga.
  • Idiosyncratic Episode Naming: Each episode is given the title of a famous book.
  • Nerd Glasses: Shinichi has these from the start. When Shinichi wakes up after Migi heals his heart, Shinichi tries putting his glasses on and realizes he now has perfect vision without them. This is the first hint that Shinichi's physiology has changed dramatically.
  • Ominous Latin Chanting: Used for upcoming episode previews and sometimes in dramatic scenes.
  • Pragmatic Adaptation: The anime is taking some liberties with the story since the original manga took place in the late 1980s and early 1990s, but the overall premise, story, and tone remain unchanged.
  • Right for the Wrong Reasons: How did the flatfoots finally bring in Serial Killer Uragami? They caught him fiddling around with the Gorn left by actual parasites.
  • Setting Update: The anime is set in 2014 or at least the 2010s. The manga was written before cellphones and the internet became commonplace, which naturally affects the plot. The update also extends to adjusting the character design from Iwaaki's 1980s style to a more contemporary one, as seen in elements like Satomi's new hairstyle and a completely different design for Kana's jerk boyfriend who no longer looks like a classic Japanese Delinquent in a military-style uniform.
  • Shout-Out:
  • Sparing Them the Dirty Work: Uda deals the killing blow to the parasite who killed and took the form of Shinichi's mother to spare Shinichi from having to kill his own mother.
  • Spoiler Opening: The opening theme sequence shows most important characters in the story like Reiko, Kana and Goto, most of whom didn't appear in the first episode. It also shows that Shinichi will lose the glasses and change his hairstyle, and hints at the death of Shinichi's mother in episode 5, as well as Shinichi's Relationship Upgrade with Murano in episode 21.