Animorphs



"''We can't tell you who we are. Or where we live. It's too risky, and we've got to be careful. Really careful. So we don't trust anyone. Because if they find us... well, we just won't let them find us."

""The thing you've got to know is that everyone is in really big trouble. Yeah. Even you.''"

- Blurb found on the back of a majority of the Animorphs books prior to book #51: The Absolute.

Five teenagers discover that parasitic aliens, Yeerks, are secretly infiltrating Earth by taking over people's minds and bodies. They encounter a good alien, an Andalite named Elfangor, who gives them the power to morph into any animal they have touched. Joined by Elfangor's younger brother and unable to trust almost anyone else, they begin a violent and secretive guerrilla war against the alien invaders.

During the course of the series, the six teenagers grow from fun-loving kids into an elite team of paramilitary troops, attacking the Yeerk invasion force wherever it is discovered. Along the way, they find allies that they never expected, enemies that prove more dangerous (and, in some cases, bizarre) than the Yeerks themselves could ever be, travel to alien worlds, and confront their own inner conflicts. Month after month of pressure begins to take its toll, and the kids are irrevocably changed from the innocent suburban youths they once were.

It supplanted Goosebumps as the most popular children's book series of the mid-1990s till the Millennium despite its incredibly dark setting and content, or perhaps because of it. Like JK Rowling, the author credits herself as KA Applegate to obscure her gender; the books were co-authored by her husband Michael Grant, an accomplished author in his own right, and most later books were ghostwritten so that Applegate could write Everworld. Applegate did still write the outlines, however, and she came back for the two-book finale.

The series heavily deconstructed the Recruit Teenagers With Attitude / Wake Up, Go to School, Save The World concept, turning what could have been a Saturday morning cartoon into pure horror. The six protagonists regularly have to confront the morality of their actions and push against the lines they are not willing to cross, and inevitably end up crossing them because there is no other choice. War Is Hell is in full effect and they have nightmares about the horrors they have to endure, in addition to the gradual loss of innocence and humanity. It is emphasized repeatedly that their efforts are not enough--the Yeerks have infinite resources, an infinite army, anyone they know could betray them, and they have to balance the war with their normal lives so no one catches onto them. All they can do is sabotage the Yeerks until the Andalites hopefully send their fleet one day to save the Earth, but in the meantime they are only delaying the inevitable.

Responding to fan reaction to the ending, Applegate wrote this letter.

The franchise included fifty-four regular installments, four extra-length specials (the Megamorphs), two Choose Your Own Adventure-style books, four backstory specials (The Andalite, Hork-Bajir and Ellimist Chronicles and Visser), a short-lived TV series adaptation by Nickelodeon, and Game Boy and PC games. A re-release of the series began in summer 2011 with new 3D/animated covers.

Now there's a best installment crowner! Please note that while it's listed under "Best Episode", this does NOT cover the TV series.

For the TV series, see Animorphs.

" I said way too quickly, then added, "
 * Aborted Arc:
 * Book 41, "The Familiar" centers on a Bad Future where the Yeerks have conquered Earth--Marco is Visser Two's host and is in charge of Earth, Cassie is a jaded terrorist and member of a resistance lead by Tobias, using the morph as Ax and looking like Elfangor, Ax is a Yeerk general that conquered the Andalite homeworld, and Rachel is crippled. The only free member is Jake, who tries to figure out what's going on. Even in-universe the world doesn't make sense though, such as how Cassie at one point uses thought-speak while human and Tobias stating that Jake is supposed to be dead, and its revealed to be All Just a Dream. As Jake awakens he hears an entity speaking that humans require "more study", implying it was a vision from the entity. Nothing in the book ever comes into play in the rest of the series and the mysterious entity is never mentioned, though it is known that it isn't the Ellimist or Crayak.
 * A few off-hand references are made to the Yeerks having some presence on the Andalite homeworld, but this never developed into anything and by her own admission Applegate just forgot about it.
 * Absence Makes the Heart Go Yonder: Marco's dad eventually gets over his wife's death... only she isn't really dead.
 * Achilles Heel: The two-hour time limit for the Animorphs. The Yeerks also have a weakness: they need to absorb Kandrona rays every three days.
 * Achilles in His Tent: Jake, for a couple books in the final story arc.
 * A Chat With Satan: Rachel's discussions with Crayak and the Drode.
 * Action Girl: Rachel. Cassie as well; she doesn't have Rachel's Blood Knight tendencies, but she could more than hold her own in combat. Loren in The Andalite Chronicles is especially impressive given that she has no special powers.
 * Adults Are Useless: Eventually averted once they find adults they can trust not to be infested. This ends in
 * Affably Evil: Visser One   comes across as a friendly Reasonable Authority Figure compared to Visser Three, although that's not saying much. In one of the prequel books, Visser Three himself seemed to fit this when he was younger/in his earlier host body, prior to becoming an Evil Overlord.
 * A Form You Are Comfortable With: The kids never find out what the Ellimist really looks like, as he usually takes a humble, benign human shape. The reader does get a vague and incomplete description of Ketrans in The Ellimist Chronicles, and the Ellimist says, after his ascension, that he chooses the humble form of a mere Ketran (in contrast to the terrifying, monstrous form Crayak chooses.) The cover of The Ellimist Chronicles most likely shows the Ellimist's favored form.
 * Alien Abduction: The Skrit Na abduct and experiment on humans for unknown reasons.
 * Alien Animals:
 * Turns out domesticated dogs resulted from
 * Megamorphs #2 reveals that is another example.
 * Alien Among Us: Ax.
 * Aliens Are Bastards: Fairly obvious with the Yeerks, but the Andalite case is far more interesting. In the beginning of the series, kids look up to their erstwhile saviors, the great and glorious Andalites, and are counting on them to swoop in and save the day. It becomes increasingly obvious, however, that Andalite military command couldn't care less about humans. In the end, their strategy for for winning the war was to bombard Earth from orbit to take out as many Yeerks as possible.
 * Alien Arts Are Appreciated: Ax's favorite TV show is "These Messages", aka commercials.
 * Alien Blood: Andalites' is dark blue, Hork Bajir have black, Taxxons have a sickly yellow.
 * In The Andalite Chronicles, Elfangor and his friend even reference how strange and unnatural they think red human blood is.
 * Alien Invasion: Yeerks invade Earth, and the Helmacrons try to...
 * Alien Sky: The Andalite homeworld has a red and gold sky with multiple moons. The Yeerk homeworld has a green sky and constant thunderstorms. In The Andalite Chronicles, Loren, Elfangor, and Sub-Visser Seven create a weird hybrid of their respective homeworlds, and the sky is a patchwork of three different kinds of sky.
 * Aliens Speaking English: Subverted, lampshaded, and played straight in various cases.
 * Aliens Steal Cable: And record every channel! The Andalites apparently show TV programs like the news and MTV in school as part of learning about humans.
 * All Men Are Perverts: Justified; the main characters are all teenagers, after all. Marco's libido is often brought up, and he does everything from trying to get Cassie and Rachel to make out to using the internet to look up scantily clad women. Jake makes fun of Marco for it, but when Cassie's in a bikini, Jake can't stop staring. Even Ax is portrayed as being a poor student because he's always thinking about girls (he's a teenager too, albeit an Andalite teenager). Tobias is the only one unaffected, most of the time.

"Rachel: No way. George Washington?
 * All Part of the Show: #14, on a haunted house ride.
 * All Planets Are Earthlike: Mostly averted, with similarities generally being more by analogy, such as Andalite vs. Earth grass despite theirs coming in shades such as red.
 * The Yeerk planet is completely different and unpleasant. Fittingly.
 * All Powerful Bystander: The Ellimist and Crayak. If one of them tries to do something, the other will fight right back to counteract them. Last time they went all out, a good chunk of the galaxy was destroyed. Now they mostly just sit back and play Chessmaster.
 * All Up to You: Cassie has two or three of these.
 * Take, for example, #29, The Sickness, in which everyone gets a fever but her; and #44, The Unexpected, in which she gets separated from the others on an airplane flight to Australia.
 * Almighty Janitor: Ax is an Aristh in the Andalite military, which is described as something like a cadet, making his rank about as low as it can get. He finally gets promoted to prince in the final book.
 * To be fair, he's also mentioned to be the Andalite equivalent of a lazy teenager.
 * Alternate Continuity: The Alternamorphs series featured two books, The First Journey and The Next Passage. They were structured in the form of a Choose Your Own Adventure type story. In the first book, the reader became part of the group that gained the morphing power from Elfangor and joined the Animorphs on their first adventure. Upon completion of this, the story continued with an adventure involving a Sario rip (rip in time). The second book involved elements from two different Animorphs stories from around the midpoint. However, the books were structured in such a way that only a single set of possibilities allowed you to continue the story. Perhaps, for this reason, the series never really caught on, has been largely forgotten, and was discontinued after the second book.
 * Alternate History: Megamorphs #3: Elfangor's Secret and Megamorphs #4: Back to Before both play with this. In #3, they follow Visser Four with the Time Matrix and experience him changing the outcome of battles and other historical events to his benefit. In #4, the Drode lets Jake see what it would have been like if they had never been given the morphing powers.
 * Always Chaotic Evil: Tends to be strongly subverted. Every time an apparently Always Chaotic Evil race is introduced, it quickly becomes clear that something more is going on.
 * The Howlers are the army of doom of Crayak, a malevolent god. A hive-mind, they've destroyed countless worlds without hesitation. The twist?
 * Hork-Bajir: Eight-foot walking razor-bladed lizardmen, who appear bred purely for combat. Turns out they're Gentle Giants, vegetarians in fact (the blades are used to harvest bark), used as host bodies by the Yeerks for their brute power. Which brings us to?
 * Yeerks: Literal brain-slugs who control your mind. But the Yeerks were largely pushed towards conquest by a hatred of their standing in the galaxy. In their natural state, they're 2-inch slugs, doomed to a blind, drab existence unless they take host bodies. Most, at least the ones we see on Earth, have embraced conquest, but there are a few who cooperate with the host rather than completely controlling it, and even fewer who are actively against the invasion. They're Often Chaotic Evil, but not always. Even those who have embraced the imperialist philosophy don't see themselves as evil, just doing what they naturally do (you don't think of yourself as evil because you kill and eat pigs, do you?); this mindset has been drilled into them with Yeerk Empire propaganda since birth.
 * Then there's the Taxxons, who
 * An Aesop: Several, including War Is Hell, and What Is Evil?.
 * And Call Him George:
 * And Then What?: The characters often try to convince themselves, and each other, that after they've saved humanity from a race of alien parasitic monsters, they'll just go back to being regular kids. Yeah, right.
 * And I Must Scream: If you're infested by a Yeerk, then your memory and body is completely at his command... And it leaves your mind and intelligence intact, completely unable to do anything other than watch your "guest" do all sorts of horrible things.
 * Animal Motifs: Each of the Animorphs has a few favorite morphs that they use consistently, particularly in battle, that tends to say something about their personality and fighting style. For instance:
 * Rachel's favorite battle morphs are grizzly bear and elephant, neither of which is particularly subtle or defensive.
 * Jake's favorite battle morph is a tiger, which is known for its intimidating appearance.
 * Marco, the clever one, uses a gorilla, one of the few animals that can manipulate things and use tools.
 * Cassie purposely chooses a wolf morph for combat, even after she acquires far more powerful animals, as she hates fighting and prefers not to seriously hurt her opponents.
 * Later in the series her Hork-Bajir morph become her default battle morph; morphing a sentient being despite her convictions that it is wrong to do so represents the conflict between her role in the war and her pacifist nature.
 * And obviously, Tobias is the hawk. Even after he regains his morphing ability, he often goes into battle in his now-default hawk form.
 * Ax also often goes into battle unmorphed, since Andalites are plenty dangerous in their natural state (extremely sharp tail blades, remember?)
 * David has the lion and the rat - the lion represents his savage fighting style, as even Jake in his tiger morph couldn't defeat him, while the rat represents his cunning and self-serving nature.
 * When Tom acquires the morphing power late in the series, the only morph he is ever seen using is a cobra. This is incredibly fitting, given his role in the final story arc.
 * Finally, Visser Three has a grab bag assortment of alien morphs, but the only one he uses more than once is the 'Eight', the bizarre eight-headed, eight-armed, eight-legged, fire-breathing abomination he uses in the climax of the first book. Besides setting up the Visser as an alien threat of monstrous proportions, this particular morph owes a lot to the Beast of Revelations.
 * Animorphism: The Trope Namer.
 * Anyone Can Die: Death of named characters is incredibly rare before the final arc begins, particularly if the character has appeared in more than one book, but quite a few of the supporting characters   are dead by the series' end.
 * But I thought Surely that doesn't mean he's dead, right?
 * Arch Enemy: Visser Three to the group collectively, although especially to Ax. And to Elfangor, before he died. Then there's Crayak to the Ellimist, Taylor to Tobias, and  to Rachel.
 * Arson, Murder, and Jaywalking: In Visser the charges against the former Visser One are read during her trial, followed by the different forms of death penalty associated with each crime. It ends almost incongruously with "... treason by murder of subordinate Yeerks, which carries a sentence of exile to punishment duty."
 * Ascended Extra: Eva, Naomi, Peter, Toby, Tom and Erek.
 * Ascended Fanboy: The Ellimist, arguably.  Also the campers from The Resistance, who are Star Trek fans on their yearly camp out to look for aliens or something. Not to mention Erek.
 * Ask a Stupid Question: During one of the Megamorphs books:

Marco: Jake, tell her, "No, Guido Washington."

Jake: Marco would like me to pass along a sarcastic remark."

"Marco: ...We'll be sitting ducks if Tom turns the Blade ship on us, and we all know that's his plan.
 * Asskicking Equals Authority: Visser Three, in The Andalite Chronicles, is a Hork-Bajir Controller with the respectable rank of Sub-Visser Seven. He's promoted to a low Visser rank immediately upon (and explicitly because of) his infestation of Elfangor's commanding officer and becomes the only Andalite-Controller in history. His rise turns meteoric from there.
 * Authority Equals Asskicking: Visser Three.
 * Awful Truth:
 * A major motif in this series is the fact that there are some things that you just can't unlearn. The kids can't, although they desperately want to, forget about the Yeerks and go on living their lives, because they now know they'd be dooming the entire planet to enslavement; to quote a Megamorphs back cover, "You can't close your eyes to the truth you know is out there".
 * Subverted in one instance, when Jake strikes a deal with Crayak to return them to the moment where they chose to walk through the construction site (where they met Elfangor and learned of the invasion). The kids walked home the safe way and consequently they had no knowledge of the Yeerks or the invasion. But, true to the theme of the series, the kids eventually have to confront the reality they didn't even know was there (made even cooler because now they don't have any powers).
 * Ax Crazy: Taylor. And probably Rachel. No, Ax is not Ax crazy. (He may act crazy around certain foods, though.)
 * David.
 * Visser Three
 * The Bad Guy Wins: Sort of. Though the kids beat the Yeerk Empire and, the , , and.
 * Badass Crew: The Animorphs.
 * Badass Teacher: Quiet, unassuming Mr. Tidwell is actually a revolutionary fighter who has a symbiotic relationship with the Yeerk inside his head.
 * Badass Normal: Loren, Peter, and Eva.
 * Bad Boss: Visser Three (promoted to Visser One during the series). Not only does he sarcastically mock his subordinates, but he kills them for little-to-no reason. Didn't kill the Animorphs? Decapitated. Made a mistake? Decapitated. Interrupted the Visser? Decapitated. Closed a door too slowly? De-fucking-capitated. You can't win with this guy, to the point where Yeerks pass over promotions because it means having to work with Visser Three, and therefore probably being decapi-SLASH- *thud*. Lampshaded: Jake points out that Visser Three's tendencies to kill his subordinates make them hate and fear him, making him (and them) less effective. He also says that that gives the Animorphs an advantage over him.
 * Bad Future:
 * There's two. The "Yeerks-have-won" future shown in #7 and the "Yeerks-have-won-but-some-of-us-still-fight" future shown in #41.
 * Subverted in Megamorphs 4.
 * Battle Cry: Rachel's "Let's do it!" and the Hork-Bajir "Free or dead!"
 * The Battlestar: Both the Blade ship and the Pool ship qualify (the former is a battleship, the latter is more of a barracks and Airborne Aircraft Carrier with big fucking guns).
 * On the Andalite side, we have the Dome ship, with the titular domed reproduction of the Andalite homeworld that detaches for greater maneuverability in combat.
 * Balance Between Good and Evil: The Ellimist and Crayak tie each other's hands as to what they can or cannot do. If one wants something, they have to make a concession. Both do plan on eventually defeating the other forever, however.
 * Beauty Is Never Tarnished: Rachel, as a human, according to everyone else. But her morphed battles have included.
 * Averted in #41:
 * Bee People: The Helmacrons.
 * The Berserker: Rachel, at times.
 * Berserk Button:
 * Tom's status as a Controller was always a source of tension, but it doesn't really reach boiling point until the second-last book:

Jake: It's not Tom! IT'S NOT TOM!! It's not Tom, don't call him that! It's the Yeerk, it's the Yeerk in his head, NOT MY BROTHER!!"

""It was a scene of perfect beauty. Blood slicked the concrete. Taxxon guts lay in steaming piles. There were bellows and cries of pain. Battle! Desperate and deadly! I almost cried at the sheer loveliness of it.""
 * Also Rachel. May God help you if you mess with her boyfriend.
 * Never, and I mean NEVER get in Ax's way if he wants the delicious and narcotic food he loves SO much...cinnamon buns.
 * Beware the Nice Ones:
 * Human-Controllers (Yeerk hosts) generally have public personae falling between "normal but caring human" (Chapman) and "Friend to All Living Things" (William Roger Tennant). The Sharing, "a Boys & Girls Club for everyone" responsible for a great deal of youth work and charity events, is a Yeerk front organization intended to recruit new Controllers.
 * Cassie, who is dangerous exactly because she's nice. Remember, she felt it would be kinder to . She also lets Tom which caused Ax to wonder if Cassie could be more dangerous than Rachel.
 * Big Bad: Visser Three takes this role for most of the books, as the leader of Yeerk forces on Earth.
 * Bigger Bad: Visser Three's the main villain of the series, but he does have mostly off-page superiors, namely the Council of Thirteen and Visser One, and then there's Crayak...
 * Big Badass Bird of Prey: A common morph for all six, although Tobias is stuck in his.
 * Big Badass Wolf:
 * All the animorphs except Tobias and Ax have wolf morphs. Cassie uses it as her main battle morph.
 * There's also a real big badass wolf, who almost threw down with Jake in a battle-of-the-alpha-males for territorial supremacy in book 3. And then later he almost kicks the shit out of a Controller Jake in book 6 when his Yeerk tries to escape by morphing to wolf.
 * Big Creepy Crawlies: The Taxxons.
 * Big Dumb Body: Why the Yeerks took the Hork-Bajir.
 * Big Eater: Ax, in human morph. Also the Taxxons, although their example is not meant to be funny.
 * Big No: David,
 * Bittersweet Ending: Oh, gosh. While the war is over and things are looking up for humankind, . Ax seems comparatively well-off to begin with, being , but.
 * Black and Gray Morality: A major theme in the books. Definitely applicable by the end of the series. Can also cover the Andalite military, who are just as bad as the Yeerks, just in a different way.
 * Blade Below the Shoulder: Hork-Bajir.
 * Blessed With Suck / Cursed With Awesome: By the end of the series, everyone is either one or the other or bits of both. (There has been quite a bit of discussion about this.)
 * RE: Blessed With Suck - The Taxxon's insatiable hunger certainly fits. The Yeerks' parasitism, which is all fine and good until one becomes conscious of one's status as a parasite. The morphing power itself may qualify, as once the kids gain it, they can't really enjoy it as they're caught up in an interplanetary war.
 * Andalites and their thought speak. It's cool being partially psychic, but the lack of mouths meant it took the Andalites centuries to develop alternatives to things like telephones.
 * RE: Cursed With Awesome - The whole Animorphs gang, really. And at least Tobias was stuck as a hawk, not a flea. Or a rat.
 * The Yeerks make the Hork-Bajir Cursed With Awesome as well. They're used as shock troops for combat because they're strong, agile, and just about every moving part on their body has a wickedly sharp blade sticking out of it. The thing is, those blades? Uninfested Hork-Bajir use them to harvest tree bark, their main food source. The whiplash musculature and quick movement come from the fact that they're an arboreal species that prefers to avoid predators entirely, rather than fight off attackers.
 * Blood Knight: Rachel tries not to fall into this. More often than not, she fails horribly. During The Separation, when she gets split into two different personalities, one of them is a Blood Knight personified, interested ONLY in fighting. She's still somewhat interested in Tobias while like this, but that interest takes a secondary seat to violence.

- The Separation.

""It's all your fault! I used to see you as a hero, Elfangor. A leader. But the truth is you just couldn't see another way out! You sentenced us to hardship and pain and suffering. We were just kids! You made us question every value we had ever learned! You had no right to heap that weight on us, huge and impossible. You used us!""
 * Bluff the Eavesdropper: Once the team realizes how unstable and dangerous David is, they sometimes do this while discussing their plans, in case he is eavesdropping on them in morph.
 * Blunt Metaphors Trauma: Ax.
 * Bluff the Impostor
 * Body Horror: Most of the morphing is this, except for Cassie, who has a talent for it.
 * Bolivian Army Ending
 * Bond One-Liner: Visser Three.
 * Bored With Insanity: The kids remark from time to time that they only thing they find strange anymore is that they don't find anything strange anymore. Constantly Lampshaded by Marco, who often remarks, deadpan, on how utterly insane their lives have become.
 * Let's see: started with aliens, added shapechanging, destroyed some spaceships, traveled through time...again, manipulated by god-alien, bartered hair and holograms for tour guide on distant planet, the oatmeal issue...and that's just the beginning.
 * Break the Game Breaker: The Animorphs get the chance to acquire dinosaur morphs when they go back in time; the ending provides a Snap Back so that they cannot use these morphs in the future; random Techno Babble at the end of the book gives us an explanation why.
 * The Bridge: The Pool ship's bridge and the Blade ship's bridge are the locations of some very important events.
 * The Brute: During the last story arc and the books leading up to it, the kids reflect that Visser Three is an incompetent tactician and instead relies on technological advantages; he's pushed for all-out war since the beginning. "[He] doesn't know tactics," Jake says, "he fights with a sledgehammer."
 * Brother Chuck: Hey, remember Mertil, the Andalite that had also survived Elfangor's ship's crash and had been living on Earth for the entire war? Remember how he was found by the kids and decided to remain in hiding? Or maybe you don't, because he was only in one book. Having another Andalite on board would've been very useful for the kids. Even if Mertil didn't join the kids for his own reasons, it would've been nice for him to get another mention, seeing as an Andalite war hero living on Earth is kind of a big deal.
 * Broken Masquerade: This escalates to the entire world when, especially in the last book of the series.
 * Broken Pedestal:
 * For Jake, at least:

"''Marco: That's it exactly.
 * Andalites in general for all of the kids.
 * Breather Novel: Book #24, The Suspicion. Tiny aliens invade Cassie's barn and try to steal the morph cube. Hilarity Ensues. Made all the more blatant as a breather because it comes right on the heels of a major Wham Novel.
 * Bring Him to Me
 * Bromantic Foil: Marco to Jake.
 * Butterfly of Doom: Visser Four in Elfangor's Secret.
 * Bullet Time: A trick frequently used by KA Applegate; when one of the characters are on the edge of death, in battle, time seems to slow down. It's never explicitly called bullet time, though.
 * Bug War: The war on the Taxxon planet in The Andalite Chronicles.
 * But Not Too Black: Inverted in the relaunch of the series, with fans complaining because the model chosen for Marco wasn't Latino enough.
 * Cain and Abel: Tom and Jake, respectively, though in an interesting subversion,.
 * That particular subversion appears to be a favorite of K.A's. She also uses it in Everworld.
 * The Call Knows Where You Live: Marco. Also, Jake and Elfangor.
 * Can Only Move the Eyes: Sometimes Controllers can break through the Yeerk's control to portray a meaningful glance or facial expression.
 * Can't Stay Normal: Inverted.
 * Capulet Counterpart: In an awesomely amoral fashion.
 * Casual Interstellar Travel: Averted. There is a hyperspace analogue called "Zero Space," but its configuration is prone to sudden shifts that may extend what was once a trip of a couple of days into months. Among other problems.
 * Cassandra Truth:
 * Nobody believes the kids the first time they explain what's going on.
 * At one point the Andalites are sending the majority of their reinforcements to the Anati system instead of Earth, believing the majority of the Yeerk fleet to be there. The kids have inside information that the Anati system situation is an ambush (the asteroid fields are rigged with automated turrets and mines). When they hear this, the Andalite command assumes the kids are lying in an effort to become a priority.
 * Catch Phrase: Everyone, in narration: "My name is [name.]" Additionally, Rachel's "Let's do it!" and Marco's "This is insane."/"Are you insane?!" also qualify. Both are frequently Lampshaded.
 * In one instance, the two switched catchphrases, after Rachel goes over their plan:

Rachel: Yeah, this is insane.

Marco: I know, right? Let's do it!''"

"Ellimist:(laughing) Did I? If I did, that would be very clever of me."
 * "That was exciting/fun/really cool." "Let's never, ever do it again."
 * Ax: "We have x of your minutes left."
 * "They're everyone's minutes, Ax."
 * Jake's "Don't call me Prince." is something between this and a Running Gag.
 * The Cavalry: During the fourth book, the Animorphs save a great one - a whale, though their dolphin morphs think of it as a great one, and the whale thinks of them as little ones - from an attack by sharks (and dolphins really do not like sharks, particularly when sharks are attacking a great one). Later on, Visser Three comes after the Animorphs in his own morph (a very, very big sea-going creature from another planet), trying to kill or capture them. The Animorphs send out a cry for help via echolocation. Cue two massive sperm whales, two slightly smaller ones, and the great humpback that they saved from the sharks earlier. Sixty feet long and weighing in at approximately sixty-five tons each, tearing in at absolute top speed to first ram Visser Three's morph, and then subsequently start beating the life out of him with their tails, using blows that are described as being quite capable of knocking entire walls down. The exact same thing happens in book 36, oddly enough, also involving whales.
 * The Chessmaster: The Ellimist and Crayak.
 * The Chains of Commanding: A major focus of Jake's personality (combined with Comes Great Responsibility and I Just Want to Be Normal). Exemplified when Rachel acts as leader for a short while and experiences the same issues, making her wonder whether being leader was the enviable position she once thought it was.
 * Changeling Fantasy: Tobias.
 * Character Development
 * Character Focus
 * Character Name Alias: Marco, Rachel, and Cassie go by: Fox Mulder, Dana Scully, and Cindy Crawford, respectively in #14.
 * Childhood Friends: Marco and Jake.
 * Child Soldiers: A major focus of the series and a deconstruction of Kid Hero and Wake Up, Go to School, Save The World.
 * City With No Name: The Animorphs refuse to tell the reader where they live, not wanting the Yeerks to read the books and find them. According to the author, she did have a specific location in mind for them, and evidence in the final book (and probably Visser) confirms their location as.
 * Cluster F-Bomb / Foreign Cuss Word: When Erek calls Jake out in the last book.
 * Color Coded for Your Convenience: Andalite technology tends to be based around the colors blue and white. Yeerk tech (at least that used by Visser Three) is usually black and red.
 * Color Me Black: Inverted when Cassie, confronted with a racist when travelling back in time, turns herself white - into a polar bear.
 * Combat By Champion: The Animorphs vs. the Howlers in book 26.
 * Comes Great Responsibility: Tobias is very serious about this in #1. Jake also notes in MM3 that their power traps them in a bind: they have enough power to fight and make them responsible, but they don't have enough power to actually win.
 * Comic Book Time: Played with. Early books in the series had the Unreliable Narrators worry about how they would adapt in winter, which implies that their adventures are taking place in Comic Book Time prior to the first winter after receiving their powers. By the end of the series it turns out that It's Always Spring because of the setting, the worries about winter playing up the Literary Agent Hypothesis that they could not give away their location, and about three years pass from beginning to end of the series.
 * Commander Contrarian: Marco, for two reasons. Firstly, because the kids' plans are usually slapped together at the last second or played by ear and therefore incredibly risky ("This is an insane plan!"); secondly, because Marco has a talent for zeroing in on inconsistencies, and wants to make the plans as effective and watertight as possible. It's said that pointing out flaws is really all Marco can do, which is what makes him a bad leader, as he's too cautious to actually get anything done. It also makes him the best tactician of the team, as is often pointed out. He couldn't make you go along with it, but he could work out a working plan well enough.
 * Common Tongue: Gallard is a galactic language designed to be pronounceable by pretty much anyone. It doesn't see much use (although Hork-Bajir occasionally lapse into it) because the primary aliens are the telepathic Andalites and the Puppeteer Parasites Yeerks.
 * Competence Zone: Anyone not in the inner circle, though this makes sense, as they have the most experience fighting the Yeerks.
 * Contest Winner Cameo: Erek King. Actually became a recurring character, and a major player in the final battle.
 * Continuity Drift: In the very first book, it's possible for a human to thought-speak with someone in morph, which is totally ignored in every single other book.
 * Due to the fairly large number of these in the series, the fandom nicknamed them KASUs or "Katherine Applegate Screws Ups/Screw-Ups" (K.A. herself eventually started using the term in interviews) and when the first few books were relaunched in 2011, they were fixed.
 * A whole list of KASUs can be found at this page: "A List of Mistakes in Animorphs".
 * Continuity Nod:
 * In #54, Ax was promoted from "aristh" straight to "Prince," calling back a conversation between Elfangor and Arbron in The Andalite Chronicles, where Arbron snarks that glory-hungry Elfangor's probably fantasizing that they'll make him a Prince without even stopping to make him a full warrior.
 * In the last book, when
 * "We're not morphing ants! We're never morphing ants again!" or some variant is said every couple books, in reference to one of the kids' earliest missions.
 * When Marco morphs lobster to get his keys from the bottom of his pool: "It seemed like a lifetime ago that me and Jake morphed lobsters to escape from the Yeerks by hiding in a grocery store fish tank. The days, man. Those were the days."
 * In the penultimate book, Jake This is exactly what  showing that Jake is now far more ruthless than Elfangor was (at least at first).
 * Conspicuous CG: You think a book series would be immune to this? Every book features artwork by David B. Mattingly, except the covers done by Romas Kukalis. Most of the first-page illustrations were created by David as either photo manipulations or photo montages. Two, however, stand out. The illustrations for Book 31 and (to a lesser extent) book 38 use more CG than normal.
 * Contrived Coincidence: The Animorphs contain Ax (Elfangor's brother), Tobias, Marco , and Cassie . The Drode lampshades this, insisting it can't be a coincidence, and that the Ellimist stacked the deck.

"Tobias: 
 * There are several apparent ones in Book #27, but it is ultimately an aversion. Erik is left unable to move or project his hologram, so the Animorphs carry him out of the mall. There was a major sale, so virtually everyone was elsewhere in the mall and all the cameras are down. They take a bus, and the bus driver doesn't notice. This makes them suspicious. Later, when they realize they will need a sperm whale morph, a sperm whale "happens" to beach itself. This they all realize can't be a coincidence, and that someone is pulling the strings. The Drode turns out to have been behind all of it.
 * Cool Starship: The kids themselves are partial to Dome ships, especially newer models like the Elfangor. The Rachel is also supposed to be pretty sweet.
 * Cosmopolitan Council: The Yeerk Empire is made up of officers called vissers, who take orders from the Council of Thirteen.
 * Covered in Mud: At one point, Cassie jokes about how Rachel never seems to get dirty - that any mud just seems to be deflected away. She throws a ball of mud at Rachel, who knocks it away without it splattering all over her. Cassie comments that Rachel's hand probably isn't even muddy, but Rachel refuses to show her.
 * Creator Provincialism: It's not really made clear what's going on outside the States during the entirety of the war. We know that at least one major head of state outside the U.S. is a Controller (the President of the U.S. isn't though), but except for, like, four missions outside the country, the kids mostly ignore everything beyond U.S. borders. Or more than a day's journey from their home town, for that matter.
 * The Cretaceous Is Always Doomed: In Megamorphs 2: In the Time of the Dinosaurs, a hole in space-time causes the Animorphs to accidentally arrive one day before the asteroid hit. They get into a tussle with several warring Ancient Astronauts trying to colonize Earth, the losing species attempting revenge by diverting the path of a passing comet. The meteor's strike creates another hole that lets the kids return to the present. It was one of the weirder books.
 * Cryptically Unhelpful Answer:

Ax: "

"Ax: He’s welcoming the visser back aboard the Blade ship. Or he may be telling him his brother is a meteor fragment. I understand Galard, but this morph’s hearing is very uncertain."
 * (It's later revealed that Andalites absorb nutrients from grass through their hooves.)
 * Curb Stomp Battle: Erek King, the millennia-old robot that is capable of generating personal forcefields and shrugging off being hit by a truck. He can move faster than the eye can follow and is described as being able to "obliterate you down to your individual molecules"; however, he's hardwired to hate violence and can never commit any violent act. In one instance, this is subverted, allowing him to rescue the Animorphs. The fight lasted less than a minute, and was only vaguely described. In the time it took you to read this paragraph Erek managed to kill dozens of Hork-Bajir. Afterwards, Erek begged to have his original protocols restored. Rachel saw it and the brutality reduced her to tears.
 * Cult: The Sharing
 * Cultural Posturing: Ax does this frequently.
 * Dark and Troubled Past: Marco. The disappearance of his mother and the subsequent split of his family caused him to become more cynical and, in effect, more ruthless and pragmatic and less attached to romantic, idealistic principles.
 * Dead Man Writing: Aldrea's stored persona.
 * Deadpan Snarker: Marco, usually, but Rachel and Tobias are both pretty sarcastic when the situation calls for it.
 * Dead Person Impersonation: David.
 * Deconstruction: In spades. Really, the whole angle of the series.
 * Kid Hero: It's obvious from the get-go that the kids, having no sort of military knowledge or practical connections whatsoever, are pretty much just making it up as they go and doing the best they can with what they have, and they're closer to Child Soldiers than anything else.
 * Wake Up, Go to School, Save The World: As you'd expect, fighting as an uncover guerrilla resistance agent tends to take up a lot of the kids' spare time and energy, and is too important to leave to an extra-curricular schedule. The war takes place at the expense of the kids' personal lives (sometimes forcing them to fight for up to, it is mentioned, three days straight without sleep) and their grades and sociability are pretty much done for by the end of the series.
 * The Good Guys Always Win: Not a full deconstruction, as, but the fact that they're massively outgunned is a major element in the story, and the kids comment from time to time that only rarely are their missions actually successful. One of the major messages of the series is that, despite idealistic platitudes, victory ultimately goes to those who are ruthless and desperate enough to take the most extreme measures, not to the morally superior.
 * Justice Will Prevail: Most of the series' villains never get their comeuppance - the Blade ship escapes and Esplin 9466 is never executed. K.A. Applegate has stated that this is meant to reflect real wars, where people are rarely held accountable for the evil they commit.
 * Violence Is the Only Option: Initially, what with this being an invasion and occupation, the kids consider armed resistance to be their only option. But it quickly becomes apparent that Yeerks are Not So Different from the Animorphs themselves, capable of being reasoned and negotiated with, and at times a pacifistic and diplomatic solutions work out.
 * What Measure Is a Non-Human?: Hork-Bajir, Taxxons and Yeerks are pretty fucking scary aliens to look at, and the kids initially assume them all to be evil monsters. However, by the end of the series, it's obvious that despite outward differences, the three species actually have much more in common with humankind than is apparent at first glance.
 * Destructive Saviour:
 * Throughout the whole series, Jake and the kids wait for Andalite reinforcements to save them from the Yeerk invasion; originally, Elfangor had promised them that they would have to fight for no more than a year. This year eventually stretches into three, as Andalites see humans as a low priority and take their time getting there. Unfortunately, by the time the Andalites arrive,
 * When the Yeerks invade the Hork-Bajir planet,
 * Eventually averted in the last book. Prior to the last book, Ax notes that . This comes to be proven true in the last book, when.
 * Death From Above:
 * In the second-last book, Visser One kills by shooting the Pool ship's Dracon cannon from orbit.
 * Tobias whenever he's feeling hungry.
 * Or in battle. TSEEEEEER!
 * Death Is Cheap:
 * In Elfangor's Secret it's known that one of the kids will have to die to set things right,
 * Derelict Graveyard: The Nartec city.
 * Descending Ceiling: Used by Visser Three to scare the Rachels in #32 because he thinks she's an Andalite and Andalites are somewhat claustrophobic.
 * Despair Event Horizon:
 * Deus Angst Machina: Pick a character, any character. Especially the auxiliary Animorphs. And, in a weird way, Loren.
 * Deus Ex Machina: To the Leeran conflict, the Animorphs could be considered this. They are not supposed to be there, show up right when all hope seems lost, and happen to have the exact abilities needed to ensure Andalite victory there.
 * Devil's Advocate: Marco would sometimes offer the Devil's Advocate view on missions.
 * Did Not Do the Research:
 * In #5, when Marco and Jake morph lobsters, they turn red. In the last book, when Marco morphs a lobster to get his keys from the bottom of his pool, he turns blue, and Applegate doesn't mention that they were red the first time around. He claims that blue is a lobster's natural color, and they turn red when they've been boiled, which isn't true. Blue lobsters and red lobsters are different phenotypes. So, not only was Applegate wrong about the boiling thing, Marco should've turned into a red lobster, considering the lobster whose DNA he acquired was red.
 * Did You Just Flip Off Cthulhu?: Jake to Crayak, repeatedly. One time, the rest of the team to Crayak by.
 * Disability Superpower: Literally. Most of the Auxiliaries are hospitalized children, as Yeerks are less likely to infest the disabled. It's mentioned that they have a much easier time controlling the instincts of a new morph, as their minds are stronger from spending so much of their lives unable to move their bodies as freely.
 * Divine Chessboard: The heroes are guided by Big Good The Ellimist, while Bigger Bad Crayak is behind the Yeerks and other adversaries.
 * The Dark Side Will Make You Forget: Affects all the kids to some degree. Rachel in particular, as can't remember what she was like before the war started.
 * Disposable Superhero Maker: Subverted when.
 * The Dog Bites Back: Guess Visser Three should have promoted him when he had the chance.
 * Do Not Go Gentle:
 * Don't You Dare Pity Me: Marco hates being pitied by the others, and often shoos Cassie away when she tries to play therapist. Jake, similarly, can't stand pity, because he feels that as the leader, he should appear flawless and confident in every decision he makes, and therefore tries never to let the others see him second-guessing himself.
 * Doomed Hometown:
 * Double Consciousness: The Morphing technology grants you your animal form's instincts as well as your own consciousness. Sometimes these play well together, sometimes not. It usually depends on how humanlike said animal is. Tobias struggled with this while in Shapeshifter Mode Lock in some early books, then came to terms with it.
 * The kids wonder about the morality of morphing, as controlling the animal's natural mind is similar to what Yeerks do to humans and the kids decide early on to never morph sapient species without the permission of the person.
 * The Drag Along: Marco initially, though he eventually grows out of it.
 * Dragon-in-Chief : Visser Three
 * Drama Preserving Handicap: Initially, it's in both sides' best interest to keep the war a secret. The Yeerks prefer a strategy of infiltration, then suddenly seizing control of the planet, in order to minimize both Yeerk casualties and the deaths of thousands of potential host bodies. The Animorphs, on the other hand, prefer the war also remain a secret, for tactical reasons: the Yeerks have much more advanced technology and would certainly win any open engagement where they were free to use all of their weapons (a bunch of animals can't do much good against Yeerk capital ships destroying cities from orbit). Also, the primary reason the Yeerks want Earth is because of the large population, and a war would reduce the value. On the other hand, there are so many damn humans compared to Yeerks (6 billion versus a couple hundred thousand) that open warfare might even hurt the Yeerks despite their serious technology because humanity could and probably would Zerg Rush any terrestrial fortifications, at least enough to turn the campaign into a Pyrrhic Victory that the Andalites could take advantage of.
 * Dreaming the Truth:
 * Drives Like Crazy:
 * It's a running gag that whenever Marco drives any vehicle, he sucks at it. In one instance Marco achieves this with an Abrams tank.
 * It's later revealed that Tobias is an even worse driver; Marco even calls him on it.
 * Drop in Character: Erek was good at walking up from out of nowhere. So was Mr. King. I guess it's a Chee thing.
 * Dumb Blonde: Subverted. Everyone outside the group assumes Rachel to be a ditzy airhead. Nothing could be further from the truth.
 * Not to mention she's a really hot teenager, so boys make hasty assumptions. They get corrected really, really fast.
 * Dying As Yourself: A host will sometimes experience a moment of freedom before death as the Yeerk will abandon them in an attempt to save themselves.
 * Earn Your Happy Ending: After years of unimaginable pressure and War Is Hell torment, the kids become the greatest heroes in the history of humanity. However, only.
 * And.
 * And, of course, thanks to the.
 * Well, except.
 * Efficient Displacement: In book #25, The Extreme, the Animorphs (as Polar Bears) are being chased by Venber at the Arctic Yeerk base. Marco stops quickly and a Venber misses him, slamming through a steel door and making a vague Venber-shaped hole in it. Marco even calls it a "Bugs-Bunny-runs-through-the-door kind of hole."
 * Either World Domination or Something About Bananas: Ax does something like this once when the kids are in fly morph:
 * Either World Domination or Something About Bananas: Ax does something like this once when the kids are in fly morph:

"Jake: He's a prisoner of war. We don't kill prisoners.
 * Eldritch Abomination:
 * Crayak.
 * The Drode to some extent.
 * There's also nearly every single one of Visser Three's morphs.
 * Electric Instant Gratification: Worked into an Electric Torture device, and proves more effective on hawks than standard torture.
 * Actually, it only works better on Tobias because of his human mind. He uses his hawk brain as a shield to numb himself from the pain, but has no way to numb himself from pleasure.
 * Elevator Floor Announcement: Marco parodies this at one point.
 * Engineered Public Confession: Or rather, an engineered public demonstration. In Book #35, after spending days harassing a particular famous-but-psychologically unstable Controller, Marco (as a poodle) provokes the Controller into attempting to strangle him to death on national TV.
 * The Eternal Churchill: The Animorphs choose fight over flight often, even if it seems hopeless. Maybe especially if it seems hopeless. The fact that humans do this mystifies Visser Three. Visser One recognizes that makes humans very dangerous.
 * E.T.GaveUsWiFi: In The Andalite Chronicles it's implied that Elfangor made friends with Bill Gates and Steve Jobs, which led to the advancement of human technology. Also played with in #45 The Revelation, when it's revealed that the Yeerks helped humans discover Zero-space. Lampshaded by Ax in the same book.
 * Even Evil Has Standards:

Visser One: No. Of course not. You merely blow up ground-based Yeerk pools and kill thousands. And then another seventeen thousand of our brothers here on this ship. Defenseless, harmless, unhosted Yeerks. Murdered. But you don't kill prisoners."

"Rachel (threateningly): What did you say?
 * Even Evil Has Loved Ones: Visser One (not, the actual Yeerk) and her , who were, oddly enough, allowed to remain uninfested during their time with her.
 * David and his parents...one assumes. It's unclear exactly how much he's really bothered by the fact that they're enslaved.
 * Really? The first thing he does is sneak out of Marco's room to try calling them. He only joins the fight after he's sure they're both Controllers.
 * He never tries to rescue them, though, not to mention his whole "who cares if the Yeerks are around" attitude.
 * It's implied he may not know if it's possible to rescue them. The Animorphs never got around to telling David about the three-day thing... or the Kandrona... or how to morph clothes.
 * Everything's Worse with Bears: Rachel, always on the edge between Action Girl and Blood Knight, loves her grizzly morph. The characters consider their polar bear morphs to be their most dangerous, with good reason.
 * Everything's Worse With Sharks: And Controller sharks, well, that's just awful.
 * Everyone Can See It: Despite initial trying to keep their relationship low-key, it was very apparent to everyone that Jake and Cassie were smitten with each other. Marco also sarcastically makes the same observation in an early novel when Rachel pulled a He Is Not My Boyfriend regarding Tobias.

Marco's thoughts: Like it was some big secret."

"[[spoiler:"You appear to be experiencing some engine trouble, Visser," Tom said, gloating.
 * Everyone Calls Him "Barkeep": The Ellimist. Oddly, Ellimist was originally his online gaming handle, which he adopted as his name when he ascended to omnipotence. His real name is Toomin.
 * And the Drode. According to the... er, being himself, it means "wild card."
 * Everyone Meets Everyone: Partially subverted. Each of the five main characters knew, or at least knew of, the other four before the series began, but they weren't close.
 * Everyone Loves Blondes: Rachel is tall, graceful, blond haired, blue eyed, glamorous, and fearless.
 * Evil Gloating: A couple times in minor books, but most notably done by

 Visser One said.

"Oh, I doubt it," Tom said cheerfully. "The Andalite fleet is rather close by. It's possible that I misled you on that point." He was all but giggling.]]"

"Rachel (narrating): But even I have enough sense to know the words "we have to win" are the first four steps on the road to hell."
 * Evil Overlord: Visser Three. The first Visser One might also qualify, as things she does are undeniably ruthlessly evil, but they're more motivated by her military goals than an inherently malicious personality.
 * Eviler Than Thou: The whole hierarchy of the Yeerk Empire, but particularly the Visser One/Visser Three rivalry.
 * Evil Me Scares Me: Rachel gets this several times- when she gets split in half; when she gets turned into a monster; when she gazes into the abyss of her soul and sees a fearsome Blood Knight staring back at her.
 * Exact Time to Failure: Ax has to give regular time reports so that the Animorphs don't exceed two hours in morph.
 * Exposed Extraterrestrials: Pretty much all the aliens, particularly the Andalites, who first thought that human clothing was part of human's bodies. Ax has trouble understanding why he has to wear clothing while morphed as a human.
 * Extruded Book Product: Roughly the entire second half of the series was ghostwritten, although KAA was still involved in coming up with the plot outlines.
 * Faking the Dead: More than once.
 * Fallen Hero:.
 * Family-Unfriendly Violence / Family-Unfriendly Death: The fight scenes in this series are quite graphic. Ripping out throats, hacking off limbs, stabbing, shooting, maiming, disemboweling - you name it, someone's done it.
 * What makes the violence notable is that because morphing heals every wound the Animorphs have, the same character can have the same limb hacked off multiple times.
 * Famous Last Words:
 * "JAKE, STOP HER!"
 * "I love you."
 * "Do the right thing."
 * Fan Nickname: Emohawk for Tobias. Hawkward for Rachel/Tobias moments. KASU for "Katherine Applegate Screws Up/Screw-Ups", or the mistakes between books by the author and her ghostwriters.
 * Fantastic Slurs: Yeerks are "slugs", Andalites are "grass-eaters", Taxxons are "bugs" or more commonly "worms", Hork-Bajir are "geniuses" and "bark-chewers", and humans are "monkeys".
 * Fantastic Voyage: In book #42, the Helmacrons take Marco hostage by invading his body. The Animorphs shrink down and go in after them.
 * Faster Than Light Travel: By means of Zero-space (Z-space for short), which is "anti-space." It shifts and reconfigures, meaning the time it takes to travel from one planet to another isn't consistent. Z-space is also where the Animorphs' excess mass goes when they morph creatures smaller than they are (as mass can't be created or destroyed), and, presumably, where they derive the mass for when they morph larger creatures.
 * This also makes travel through Z-space dangerous, as that excess mass is physically present and can be crashed into.
 * Fate Worse Than Death: Ironically,
 * Fictional Counterpart: WAA (Web Access America) = AOL, Jeremy Jason McCole = Jonathan Taylor Thomas, Power House = Home Improvement.
 * John Berryman (Visser Four) isn't quite a Fictional Counterpart of John Barrymore, but he was a Shakespearean actor, though not a very good one.
 * Fighting From the Inside
 * Final Battle: A pretty epic one, too, although the main characters don't directly participate in it. (Jake even describes it as the "final battle").
 * Final Speech: Hirac delest is an Andalite term for one's last thoughts or final words. It is a fairly common practice among Andalite warriors to record it just before their demise. The Andalite Chronicles takes this concept Up to Eleven, as the entire text actually serves as Elfangor-Sirinial-Shamtul's hirac delest.
 * Fire-Forged Friends: How the Animorphs became friends. Before the meeting with Elfangor, they weren't close - Marco and Jake were best friends, Cassie and Rachel were best friends, but Rachel and Jake weren't close cousins, Cassie and Jake only barely knew each other, and Rachel and Marco only knew of each other. Nobody knew or liked Tobias much, and, of course, they had never met Ax. But as Marco notes, after someone saves your life a couple times, you tend to cut them a little slack.
 * First Episode Spoiler: Tobias is  and Jake's
 * Five-Man Band: It's pretty much unanimous that they ARE a five man band, and that Jake is The Hero and Rachel is The Big Guy, and it's generally agreed that Marco is The Lancer. But good luck getting people to agree on where Cassie, Tobias and Ax fall in the dynamic. See also The Chick, above, and the Animorphs Discussion page.
 * Five Token Band: Jake and Rachel are Jewish, at least on their fathers' sides, Cassie is black, Marco is half-Hispanic, Tobias comes from a very broken home, and Ax is an alien.
 * Flanderization: Rachel, though it was intentional.
 * Flashback Nightmare: Often, but mentioned more than seen.
 * Floorboard Failure: In The Reaction, Rachel involuntarily morphs an elephant on the second floor of her house, causing the floor to collapse.
 * Flowers for Algernon Syndrome: Tobias' Shapeshifter Mode Lock and morphing ability. Poor lil' Emohawk can't catch a break.
 * Foil: All over the goddamn place. All the main characters act as foils to each other to some extent.
 * Marco is foil to Jake (taking orders vs. giving orders), Tobias (pragmatism vs. idealism), Cassie (pragmatism vs. moral relativism) and Rachel (subtlety vs. brute force).
 * Jake is foil to Marco (taking orders vs. giving orders), Rachel (leadership vs. insubordination; they say this is what happens when two "strong" personalities mix), Tobias (confidence vs. insecurity) and Ax (leadership vs. loyalty to authority figures).
 * Cassie is foil to Marco (pragmatism vs. moral relativism) and Rachel (peace vs. conflict).
 * Tobias is foil to Rachel (peace vs. conflict), Jake (confidence vs. insecurity), and Marco (pragmatism vs. honor).
 * Rachel is foil to Marco (subtlety vs. brute force), Jake (leadership vs. insubordination), Cassie (peace vs. conflict), Tobias (peace vs. conflict) and Ax (giving orders vs. taking orders).
 * Ax is foil to Jake (giving orders vs. taking orders), Marco (pragmatism vs. "warrior ethics"), and Rachel (emotionality vs. logic).
 * Foot Focus: As morphing results in lost or destroyed shoes, the Animorphs are frequently barefoot. Every book mentions this fact and sometimes describes what the characters are feeling underneath their feet as they go about their adventures.
 * Foregone Conclusion: All of the Chronicles books, to some extent, by way of being stories told in flashbacks about established characters.
 * The Andalite Chronicles is narrated by Elfangor, who died in the first book. His commanding officer is Alloran, the host body of Visser Three. Even if you didn't know either of these things before reading, the Framing Device is Elfangor transmitting his last testament telepathically to his ship minutes before he dies, and he mentions being responsible for creating the Abomination, Visser Three.
 * The Hork Bajir Chronicles is about the invasion of the Hork Bajir homeworld by the Yeerks. At the start of the series proper, all of the Hork Bajir are enslaved by Yeerks.
 * Visser is about Visser One giving testimony about her invasion of Earth while on trial for treason. It is obvious from the series proper how successful she was.
 * The Ellimist Chronicles is the Ellimist telling a deceased how he became the godlike being the main characters know him as.
 * Foreshadowing: Book #17:

"Cassie: "I wonder if there's a limit to how many morphs you can do."
 * The Ellimist Chronicles begins and ends with the Ellimist visiting a dying Animorph. He admits that he did not cause him/her to be an Animorph, and that it was random chance. According to Megamorphs 4, this means that this can only be.
 * For Want of a Nail: The cause-and-effect domino line in this series is staggering. Remember, while the kids' part of the story only lasts three years, the entire conflict lasts over two decades, with the kids only jumping in near the end. Much of what happens earlier in the war only has a real effect on the story as the war reaches its conclusion. What if the Skrit Na had never kidnapped Loren and Chapman? No Animorphs, no war on Earth period. What if Arbron hadn't been trapped as a Taxxon? Earth would've been successfully taken over by Yeerks.
 * And my personal favourite: What if a pubescent Jake had felt the need to act macho to impress his crush Cassie? Planetwide Andalite genocide and enslavement and an unstoppable Yeerk Empire.
 * But then, this entire trope is justified; an Ellimist did it.
 * Forgot I Could Fly: Sometimes they forget the different abilities their morphs have.
 * There is something of a Running Gag with them forgetting that cockroaches can fly. Subverted once, where narrator remembers that cockroaches can fly and attempts to do so, only to remember that cockroaches can't fly well.
 * Four Star Badass: General Doubleday.
 * Though, as Jake notes, his rank isn't very intimidating to any of the Animorphs; "After you've stared down the likes of Ellimist and Crayak, you don't quiver just because some guy has stars on his shoulder."
 * Framing Device: All of the Chronicles books. The Andalite Chronicles is presented as Elfangor's last testament (known by Andalites as a hirac delest), given in the final moments of his life. The Hork-Bajir Chronicles is told to Tobias by Jara Hamee sometime between books 13 and 23. Visser has, by far, the most in-depth one, switching back and forth between Visser One's memories and her present-day trial. Finally, The Ellimist Chronicles is narrated to a then-unnamed dying Animorph, indicating that one of them, at the very least, will be Killed Off for Real.
 * Freak Lab Accident: How the Ellimist became a godlike being. Having his consciousness spread across multiple advanced bodies, some remaining in space and some in Z-space while the rest was sucked into a black hole, allowed his consciousness to integrate with the fabric of the universe. However, he notes that while the odds of this happening once were astronomical, the fact that it happened meant that Crayak could replicate it.
 * Friend to All Living Things:
 * Cassie. To the point where, as a Yeerk incredulously discovers, she feels guilty about killing a termite queen.
 * The Pemalites were biologically designed to be a Planet of Hats for this trope.
 * Frickin' Laser Beams
 * A Friend in Need
 * Future Badass: #41 again.
 * "A body a Yeerk would give three ranks for."
 * Gambit Roulette:
 * Gender Bender: Tobias in Animorphs 43: The Test; morphs into Taylor
 * Of course, he morphed into Taylor from his hawk body.
 * General Ripper: Alloran. Although, to be fair, he had a point.
 * Genetic Memory: Howlers, though . Andalites also possess a genetic memory, though it's much more random and is only triggered as a near-death-experience; gains it after.
 * Genre Savvy: Marco shows a strong indication that he knows he's in a fairly dark series with a rather sadistic author whenever he's being a Deadpan Snarker.

Marco: "I guess we'll find out. Probably at the worst possible time.""

"Marco: Now I have a new superstition. Anytime I'm not worried, I worry.
 * Later in the same book, upon being told they're not comic book heroes, he makes the rather prophetic comment: "Yes, but I really really want it to be a comic book. See in a comic book the heroes don't get killed."

Marco: I'm paranoid, sure. But that doesn't mean I don't have enemies."

"Crazy Helen:"...It's a big roan mare. She's acting all funny. Like maybe she's been eating the loco weed."
 * Getting Crap Past the Radar: #14: The Unknown:

Rachel: "Loco weed?"

Cassie: * shrugs*"

""Humans have fought thousands of wars. Thousands! We as a race have fought a mere handful. They run straight into the bullets, Visser Three, again and again. Did you know that? They attack against insane odds. They defend what can’t be defended. Outnumbered, outgunned, surrounded, hopeless, they will still fight, fight, fight till they are each and every one dead. Something you might know if you stopped posturing long enough to learn something!""
 * Edriss's backstory in VISSER is full of this. She spent a few years lounging around on drugs, for one thing.
 * Glamour Failure:
 * Other than that, one of the really disturbing things about this series is that, for the most part, there is no Glamour Failure on the part of the Yeerks; their replacement and impersonation of their host is so thorough and effective that even their closest friends and family never notice the difference. There is a subtle change, though: Marco notes in an early book that "Tom just hasn't been acting like Tom" after the kids realize Jake's brother is a Controller. Similarly, Melissa notices that her parents, who are Contollers, always seem insincere. The Yeerks essentially rely on the fact that no human would automatically assume that a subtle change in personality would mean an alien parasite in their head.
 * Near the end of the series, there's a lot more Glamour Failure in the series. For example, Tom will disappear for hours without giving an explanation. In one instance he mutters to Jake about how he's "preparing" for something. Justified in that by the end the Yeerks have amassed enough power to forget stealth and secrets, and are simply waiting for the orders for an open war.
 * God for A Day: Rachel was given the chance to become the ultimate fighting machine by Crayak. However such things are not much fun for a Blood Knight and it leaves only the satisfaction of sadistically snuffing out your enemies which is a road she doesn't feel comfortably going down when Crayak starting saying she is Not So Different.
 * Godwin's Law of Time Travel: Subversion: Visser Four rockets through the time stream, altering the results of battle to see to it that the human race is more cowed and easier to enslave. He goes to D-Day to ensure a Nazi victory, but
 * Then
 * Goggles Do Something Unusual: During the David Trilogy, the Animorphs try to infiltrate the Marriot resort as seagulls, but a Human-Controller wearing sunglasses is able to stun them and other birds with his sunglasses from a distance.
 * Go Out With a Smile:, in the final book.
 * Going Native: in The Andalite Chronicles. Also  in the same,  in The Hork-Bajir Chronicles,  in The Ellimist Chronicles  and  and, to a degree,  in Visser. Those Chronicles books certainly did follow a formula, didn't they?
 * Also, Ax, to a degree. By the end of the series he's arguably more human than Andalite in terms of personality and habits.
 * Good All Along: Yeerks, like humans, aren't all evil. While most Yeerks, such as Visser Three, genuinely are evil and support the imperialist philosophy, some Yeerks are part of a Yeerk Peace Movement dedicated to the creation of artificial, non-conscious host bodies Even more startling: Some of the Yeerks who inhabit host bodies are children, who are given the choice between participation or execution.
 * It's implied that even the imperialist Yeerks are only like that because they've been spoon-fed Empire propaganda since birth. As Cassie puts it: "They don't know any better. If you were raised since birth on Empire propaganda, you'd fight to take over Earth, too."
 * Not to mention their natural form is very much And I Must Scream. If the only way for you to see, taste, build, basically be anything more than a slug was to take over a sentient being that could do those things, well...many humans would not be strong enough to pass that up either.
 * Taxxons are actually intelligent creatures who posses an unfortunate evolutionary trait: They're constantly hungry. When they see an open wound they go insane with hunger, "it's like watching sharks react to blood in the water." Because of this, the Taxxons have been pressed into bondage by the Yeerks, who feed them.
 * Not even "pressed into" bondage; they willingly offered themselves to the Yeerks as hosts in hopes that the Yeerks would be able to suppress their insane hunger. It didn't work.
 * Good Republic Evil Empire: Played with a bit, as the Yeerks are clearly an empire and the Andalites a kind of republic, but the vast majority of Andalite government and military leaders the characters meet aren't much better than the Yeerks.
 * And oddly, while the Yeerk Emperor is chosen for life by the Council of Thirteen, the Council itself is democratically elected; meanwhile, the Andalite government is practically a junta; specifically, the Andalite civil government is apparently democratic, but it is implied that, over the decades-long Yeerk War, their military has (intentionally or unintentionally) usurped a large degree of informal autonomy.
 * Good Thing You Can Heal: Very often.
 * Grand Finale: The final two books.
 * G-Rated Drug: Instant maple and ginger oatmeal is addictive to Yeerks, replaces part of their brain stem, eliminates their need for Kandrona rays, and drives them insane.
 * Graying Morality: It starts off as a typical children's sci-fi with the Yeerks as evil and the Animorphs, and by extension the Andalites, as the good guys. This doesn't stick.
 * Grey and Gray Morality
 * The Greys: The Skrit Na, who like to abduct people and perform bizarre medical experiments on them for no discernible reason. The other characters note this but don't spend a lot of time trying to figure it out.
 * Growing Up Sucks: Especially when you're trapped in an interstellar war to save human freedom at age thirteen.
 * Groin Attack: Rachel does this to a male Controller once.
 * Healing Factor: One of the perks of the morphing power. As long as you can survive the injury long enough to morph or demorph, you're golden. And since the morphs are based on DNA, not the physical condition of the target, a person can acquire a morph of an injured (though it still has to be living) animal and turn into it at full health..
 * Hammerspace: Zero-space.
 * Hannibal Lecture: Tobias uses this while Taylor is torturing him. And later, Sixth Ranger Traitor David brings it back in his attempt to break Rachel's will to fight.
 * Happy Place: When Taylor figures out that simply torturing Tobias won't work, she starts sending him to his Happy Place too, attempting to shatter his mind by jumping from pure pleasure to pure pain.
 * Although interestingly enough, you could also argue that she tries this method specifically because Tobias is sending HIMSELF to a Happy Place (albeit not a terribly happy one) in order to keep from breaking down. Up until that point, he'd been surviving Taylor's methods by hiding in the hawk half of his mind, which, being the brain of a wild animal, was much better at living with pain without suffering deep psychological damage than his human side was. That's why the Happy Place method was so effective- the hawk brain was good at dealing with pain, but it didn't know what to do with happiness, which isn't something that a hawk brain understands. The happiness was just too tempting for Tobias' human side, and it drew it out of hiding- at which point Taylor slammed down on the pain button again and wacky fun ensued.
 * Heel Realization: Rachel has one after she threatens to kill David's parents.
 * He Knows Too Much: Not advocated, but suggested, when the group talks about David. It makes everyone very uncomfortable.
 * Heroic BSOD: Many, many; particularly Cassie in "The Departure" and Jake in "The Ultimate" and "The Beginning".
 * Heroic Vow: Two major ones. Firstly, the kids will never morph a sentient species without the individual's express permission. The other vow is a little more vague: The kids "fight Yeerks, but won't become them". This essentially means the kids agree to not use the same underhanded tactics Yeerks use (cold-blooded murder, ganging up on a single enemy, et cetera); this is so that the kids can try to maintain their morality while fighting a guerilla war in which they are hopelessly outgunned.
 * Heroic Sacrifice: Tobias counts for this one right from the very first book, The Invasion. During the battle under the school, he chooses to attack one of the Hork-Bajir ready to infect Cassie with a Yeerk. This in turn leads to him ultimately being trapped as a Red-tailed Hawk, permanently. He gets better, though. Sorta. Although the characters begin to wonder if it was intentional.
 * Heterosexual Life Partners: Gafinilan and Mertil if you care to read it that way. Briefly Marco and Ax, arguably, after.
 * Jake and Marco.
 * He Who Fights Monsters: Some of them were seriously at risk of slipping into this as the war ended.
 * Hey That's My Line: Rachel's reaction whenever somebody else says, "Let's do it."
 * Hidden Depths: In the final story arc,
 * Historical In-Joke: Erek was FDR's butler and coined the phrase "New Deal" in a card game. He also worked on the Pyramids and did Catherine the Great's hair. Elfangor also talks about his human friends "Bill" and "Steve" and their primitive ideas regarding computers.
 * Also, Mr. King was the one who suggested heat to Pasteur as a means to kill bacteria. Also, remember that painting of Washington crossing the Delaware? The kids go back in time and find out the river and the night were freezing. So not only did the kids see first-hand that Washington never posed like that, they directly state that if he posed like that in the middle of the night on the front of a boat crossing an ice-cold river, his soldiers would have thought he was a loon.
 * Hitler's Time Travel Exemption Act: Visser Four actually hoped to find Hitler and warn him of the Allied invasion on D-Day. Trouble is, . So rather than being of assistance, Visser Four is captured and imprisoned.
 * Hive Mind: Howlers. And Taxxons, through The Hive. Taxxons can voluntarily cut themselves off from The Hive, though, and they do when the Yeerks arrive.
 * Holding Back the Phlebotinum: The instant maple and ginger flavored oatmeal is only referenced in one book. In their defense, as Jake points out, battles that involve oatmeal will never really end up being historical.
 * Also, if Erek King could fight, the war would be over in about a week. Unfortunately, while he recognizes the necessity of the kids' cause, he himself finds violence to be too horrific to participate in (largely because his memories of the experience never fade) and is programmed to never commit any violent act.
 * Hopeless War: The Animorphs' objective isn't to win, but to at worst slow down the Yeerk invasion before the eventual loss and at best to slow down the invasion until the Andalite reinforcements arrive.
 * Holding Out for A Hero: While they try to slow the invasion on their own, the kids spend the better part of the series waiting for Andalite rescue. And waiting. And waiting. And waiting...
 * Horror Hunger: The Taxxons.
 * Hot Amazon: Rachel. Her boyfriend is, predictably, the Non-Action Guy, Tobias. It's clear who wears the pants in the relationship.
 * Rachel's amazon status is even more impressive when you consider that Tobias (who is also a guerilla warrior nonpareil) hunts and kills his own breakfast every day.
 * Also his lunch and dinner. But not a midnight snack. He's diurnal.
 * Hot Mom: Eva.
 * Hour of Power: The 2-hour time limit.
 * Hufflepuff House: The Yeerk Peace Movement, anything in the Anati system, the Rakkam Garroo conflict, the free Hork-Bajir.
 * Hugh Mann: Played straight with Ax, who, in human morph early on, is just not quite right, thanks to a cocktail of misunderstanding human humor, taking directions too literally, and having access to taste buds. By the last third of the series, he's become much better at passing for human.
 * Completely averted by the Yeerks, as human-Controllers play their parts perfectly 99% of the time.
 * Hulk Speak: The Hork-Bajir.
 * Humans Are Bastards: Ax becomes disgusted with humans during Megamorphs #3, when he sees the nature of human wars. He claims that though the Andalites had their own wars, they were never as pointless or sadistic as human wars were. He also claims that Andalites never deliberately killed children or committed genocide to other Andalites.
 * Humans Are Special: Both serious and not-so-serious examples. A prime example is the Yeerk designation of humanity as a "Class Five" host. They are intelligent and numerous but at the time of discovery possessed few natural or technological defenses against Yeerk infestation. They failed to count on human adaptability, though...
 * One notable example is Ax's observation that the Animorphs are using the morphing technology in ways the Andalites never even considered, in weaponizing it and acquiring dozens of different morphs for different situations, especially in so short a time. Most Andalites use it for subterfuge, and tend to specialize, only acquiring one or two animals over the course of their entire lives.
 * That's not all there is to his observations, either. In the very first book from his point of view he noted that humanity went from basic powered flight to moon landings in a quarter of the time it took Andalites.
 * The sheer length of series entry on that page should say something about how much this trope plays a part in the series.
 * The first Visser One in the series had this to say:
 * Humans Are Special: Both serious and not-so-serious examples. A prime example is the Yeerk designation of humanity as a "Class Five" host. They are intelligent and numerous but at the time of discovery possessed few natural or technological defenses against Yeerk infestation. They failed to count on human adaptability, though...
 * One notable example is Ax's observation that the Animorphs are using the morphing technology in ways the Andalites never even considered, in weaponizing it and acquiring dozens of different morphs for different situations, especially in so short a time. Most Andalites use it for subterfuge, and tend to specialize, only acquiring one or two animals over the course of their entire lives.
 * That's not all there is to his observations, either. In the very first book from his point of view he noted that humanity went from basic powered flight to moon landings in a quarter of the time it took Andalites.
 * The sheer length of series entry on that page should say something about how much this trope plays a part in the series.
 * The first Visser One in the series had this to say:

"Cassie: Were the nachos good?
 * Humanity Ensues:
 * Ax, by combining DNA from all the kids, makes his own human morph. He's weird.
 * Also, an ant morphs Cassie. The results is so horrific that even Cassie thinks it should be euthanised. In the same book, a buffalo morphs Chapman; as buffalo have a sense of individuality and more intelligence than an ant, this doesn't go over quite as poorly.
 * Humans Through Alien Eyes: Ax, Elfangor. And in Visser, Visser One.
 * Humiliation Conga:, after spending his entire arc being a self-centered Jerkass. He thinks he's pulling one on but he's really being lined up for a Fate Worse Than Death.
 * Also
 * Humorless Aliens: Andalites don't seem to understand the human sense of humor or its purpose, though Ax gets better at is as the series progresses.
 * Hundred Percent Adoration Rating:
 * Hurting Hero: All of them.
 * Hyperspace Is a Scary Place: The kids are, in one, instance, "pulled" into zero-space while in morph; that is, their consciousness was pulled into their extruded mass left in zero-space. Zero Space is - not pretty.
 * I Always Wanted to Say That: Rachel and "It Was a Dark And Stormy Night."
 * Marco and "Let's do it," Rachel's catchphrase. He just wanted to say it first.
 * Jake and "Charge!"
 * In an interview, KA Applegate stated that Rachel's "Dark and stormy night" and "I always wanted to write that" lines were Applegate speaking to the readers.
 * I Ate What?: Sort of. Ax eats all kinds of stuff (cigarette butts, engine oil and a paper plate to name a few) but it doesn't really bother him. He can't see what the others are getting so upset about.

Ax: They tasted of grease and salt. Plus, there was another flavor that reminds me of some delicious engine oil I tried once. Oil. Oil-luh.

Jake: Ax...You know how I mentioned you can't eat cigarette butts or dryer lint? Add engine oil to the list."

"< I will gladly fight this Controller, and even, in fair battle, kill him, but I am not a torturer. >"
 * Idiosyncratic Episode Naming: The regular series books are all in the form of "The ." Likewise, the three prequel books are all in form of "The  Chronicles."
 * If I Wanted You Dead: The second-last book. Not only could Tom have fought them with his battle morph (jaguar), but he could've conceivably called in every Hork-Bajir-Controller on the planet and taken them down.
 * If You Die I Call Your Stuff
 * If You Kill Him You Will Be Just Like Him:
 * I Just Want to Be Normal: During the war, pretty much everyone except Rachel.
 * I Know You Are in There Somewhere Fight: Rachel tries to talk Tobias into controlling his Deinonychus morph, first by appealing to his humanity. But when that doesn't work, she grudgingly tries to accept the fact that he's a bird now.
 * I Know Mortal Kombat: Marco tries to use knowledge from video games to drive a truck and operate a tank. He doesn't kill anyone (trash cans excepted), but he does scar them for life.
 * Immortality: The Ellimist and Crayak are Type I, the Animorphs (and anyone else who can morph) is Type III, and during their adventure back in time (MM 3), Jake (and the others, after his death) are Type VII.
 * Imperial Stormtrooper Marksmanship Academy: Visser Three: "Would it be asking too much for one of you to actually hit something?!!"
 * Justified in that most of the Yeerk Laser weapons were developed for Hork-Bajir use and humans find them unwieldy to aim and use.
 * And to be fair, they hit more often than most "Stormtroopers" they just never get a kill.
 * Imported Alien Phlebotinum: The Escafil Device, which transfers the morphing power.
 * Impostor Exposing Test: In The Unexpected, Cassie, hiding from the Yeerks on an airplane, tries to pose as a passenger. The Yeerks, knowing she's the only one on the plane who hasn't been affected by their paralysis-inducing phlebotinum, ferret her out by shooting everyone with low-intensity Dracon beams and seeing who flinches.
 * Incredible Shrinking Man: Happened twice. Both involved the Helmacrons.
 * Informed Judaism: Jake and Rachel are presumed Jewish (most of their parents and siblings have Hebrew names, and Rachel flat-out states "My dad's Jewish," when they visit D-Day. Dialogue from #21 and #31 allow us to conclude that their dads are brothers.), but nothing of their beliefs or holidays is mentioned beyond that.
 * In Harm's Way: Rachel. Also everyone else besides Cassie to a lesser extent.
 * The Internet Is for Porn: Actual pornography is implied once or twice, but this being a kids' book, we get a more toned-down version: Marco uses the internet almost exclusively to look up scantily clad girls.
 * Insectoid Aliens: The Taxxons.
 * Interspecies Romance: Aldrea and Dak Hamee, Elfangor and Loren. Also, Tobias and Rachel, sort of (Tobias is stuck as a hawk, but he was originally a human and thus identifies as one. )
 * I'm Not Doing That Again: Frequently used as a catchphrase, but once very serious, when the kids morph ants - the ant morph has some very disturbing side effects.
 * Cassie also says this when she leaves the Animorphs for a brief period, referring to a particularly grisly battle.
 * Ax also drops this one in #31, after torturing Chapman.
 * Cassie also says this when she leaves the Animorphs for a brief period, referring to a particularly grisly battle.
 * Ax also drops this one in #31, after torturing Chapman.

"Rachel: Just us. Just us against an enemy that could become any living thing. An enemy that could be anywhere, at any time. An owl in a tree, a spider in your house, a cat in the night, and then... Then, when you were unprepared, when you were vulnerable, a lion or a tiger or a bear.
 * Innocent Aliens: Subverted in a variety of ways. Much like Always Chaotic Evil, even the good guys have their flaws.
 * Andalites are the "good guys" and Ax often points out the immorality of human actions for Aesop effect - for instance, he states that human wars are often pointless and needlessly cruel. However, setting aside the horrifying ruthlessness of the Andalite military, Andalite citizens themselves are no saints. They have a variety of distasteful flaws, such as extreme arrogance. Most notably, they intensely hate vecols - the disabled, who, they believe, should ostracize themselves from society to preserve themselves from the shame of being "incomplete" and therefore worthless. Most notably seen when Ax strongly objected to the recruitment of the Auxiliary Animorphs, as he didn't want to fight beside human vecols.
 * Hork-Bajir used to be a species of Innocent Aliens. It wasn't that they were pacifist - they simply didn't understand the concept of fighting. The Yeerk-Hork-Bajir war, however, changed that. Hork-Bajir are still simple pacifists in nature, but they're far from the Innocent Aliens they used to be.
 * Also,.
 * The Pemalites may fit this trope, though the kids never meet the Pemalites themselves, as they were killed by the Howlers thousands of years ago.
 * And the mind-reading giant frogs, the Leerans.
 * It's All My Fault: Jake, concerning every single thing that goes wrong.
 * It's Personal: David and Rachel.
 * It's Up to You: Combines with Comes Great Responsibility. The kids are the only ones who know about the invasion who also have the power to resist it. If the kids give up, Earth is doomed. This doesn't make them happy.
 * Jerkass: David. Marco too, sometimes, but he's a nice guy, really.
 * Jerk Justifications: David's vary. They range from "I just lost my home and my parents so I'm allowed to be a total dick, boo hoo, everyone please feel sorry for me" to "I'm a dick because you're all terrible, evil people". None are very convincing. One gets the idea that David's just... a dick.
 * Kangaroo Court: Visser One is tried as a traitor and an Andalite sympathizer, but in actuality, Visser Three set up the whole thing and convinced the Council to go through with it in order to usurp her position.
 * Kick the Dog: Literally. To keep alleged Friend to All Living Things William Roger Tennant from recruiting for the Sharing, Marco morphs his stepmother's annoying poodle and torments Tennant every minute possible, with the namesake result televised live.
 * Kill the Poor: One of the Megamorphs books begins in an alternate universe where the homeless "are rounded up and shot."
 * Killed Off for Real:.
 * Kind Restraints: The team has to tie up Jake when he's accidentally infested, to starve out the Yeerk in his head, and they have to constantly watch him on top of it, because they know the Yeerk will try to morph to free him from the restraints.
 * Knight of Cerebus: While the series was never particularly lighthearted, the events of the David Trilogy really ushered in the War Is Hell era, forcing the heroes to take extreme measures to attain victory.
 * Know-Nothing Know-It-All: Rachel's mother Naomi, who doesn't adapt well to going from high powered attorney to camping with aliens and subordinate to her teenage nephew.
 * Not at first, but Naomi eventually proves herself rather useful, helping the Hork-Bajir draw up their own Constitution and persuading Captain Olston to lend his support to the team.
 * Know When to Fold Em:
 * Lampshade Hanging: Generally, tropes in this series are lampshaded if they aren't deconstructed or subverted (though a couple are played straight).
 * La Résistance: Twice, actually. The premise of the series is one, the final arc is the second.
 * Large Ham: Marco. Especially during any of the few Breather Novels.
 * Laser-Guided Amnesia: Rachel in MM1.
 * Averted with
 * Last-Name Basis: Chapman. In the main series, he's the main characters' assistant principal, so it's rather understandable that they refer to him by his last name, with or without a Mr. In The Andalite Chronicles, however, he reveals that his first name is Hedrick, but he prefers to be called Chapman, anyway.
 * Left Hanging:
 * The reader never finds out who burned down Joe Bob Fenestre's house. For that matter, we never find out what happened to Joe Bob Fenestre at all.
 * Did Rachel ?
 * In #41, the whole Bad Future thing turns out to be a mind exercise brought on by some other entity that is studying humans. It's not Ellimist or Crayak... So who was it?
 * The ending of the whole series, actually…more or less.
 * Les Collaborateurs: Some members of The Sharing. In an alternate timeline where the kids didn't meet Elfangor, Tobias became one, albeit because The Sharing was able to appeal to his lack of friends.
 * Light Feminine and Dark Feminine: Cassie and Rachel respectively have shades of this.
 * Funnily, not to be confused with their inverted skin tones.
 * Also, possibly Rachel in The Separation, when she literally splits into two different people after her starfish morph goes wrong. One is timid, caring, gentle, and pacifistic; the other is dark, ruthless, and obsessive.
 * Lightning Bruiser: Many of the kids use Lightning Bruiser-esque animals as their battle morphs. Jake's tiger and David's lion are the most obvious examples, but Rachel's bear and Marco's gorilla can also motor when they have to, while remaining very, very, strong.
 * Literal Surveillance Bug: The Animorphs use insect morphs to spy often.
 * Lilliputians: The Helmacrons (though they might fit better under Lilliputian Warriors)
 * Line in The Sand: Literally. After the Yeerks find out where the Hork-Bajir valley is located, they plan to storm it and kill everyone. Jake and his friends attempt to explain to Toby that going into battle is suicidal, and to demonstrate his point Jake draws a line in the sand and asks the Hork-Bajir to vote on which course of action is the smartest. Jake's point backfires when every Hork-Bajir votes to fight back.
 * Literary Agent Hypothesis: Mentioned at the start of every book, but it gets weird because
 * Living With the Villain: Jake's brother was a Controller.
 * Loads and Loads of Characters: Let's see: Jake, Marco, Cassie, Rachel, Ax, Tobias, Tom, Eva, Peter, Loren, Naomi, Jordan, Sara, Chapman, Erek, Visser Three, Visser One, Toby, Jara Hamee, Mr. King... And none of those are one-shot characters, either.
 * Long Running Book Series
 * Losing the Team Spirit: The group breaks up for various reasons once or twice. And near the end of the series there's a period where they all fucking hate each other.
 * Luke, I Am Your Father: Twice.  has been taken over by the leader of the invaders.   was the war hero alien who gave them their powers. Justified late in the series; the Drode whines that.
 * MacGuffin: Several over the course of the series, including the Pemalite crystal, the blue box, the Anti-Morphing Ray, and the Pemalite ship -- but the ultimate MacGuffin is the Time Matrix, which was the catalyst to the Andalites and Yeerks even discovering Earth, let alone the war itself.
 * Mad Scientist's Beautiful Daughter: Estrid.
 * Made of Iron: Because the kids can morph or demorph to heal all bodily injuries, it takes a lot to kill them. Typical battles include at least minor injuries. More commonly the kids suffer major injuries; arms being cut off, major blood loss, et cetera. The most memorable example was in the second last book, when Jake, woozy from blood loss, gets shot in the fucking head by a human-Controller. Miraculously he survives long enough to demorph.
 * Bear-Rachel getting an arm cut off and using it as a weapon also qualifies as memorable.
 * Possibly Lampshaded or Didn't Do the Research. In the first book, after morphing Homer the golden lab, Homer-Jake identifies the "other dog" AKA real Homer "was neutered, just like him." The cloned DNA wouldn't have carried over the neutering process' result.
 * Applegate rectifies her mistake later in the series. When Ax morphs a neutered bull, the kids expect him to be docile. But because he absorbed unaltered DNA, Ax is very temperamental. The kids figure out why, so the dog thing could possibly be chalked up to an Unreliable Narrator, who, uh, didn't really know what a neutered dog looked like? Okay, so it doesn't make much sense, but she corrected her mistake is what I'm saying.
 * Also, after reassuming the original form, the morpher's bodily injuries could theoretically be healed. In Megamorphs 2, Tobias says that he should be able to heal his broken wing after morphing and demorphing. Ergo, any bodily injury sustained in the original form of the morpher should be repaired, including brain damage, amputation and the like. Age would remain unaffected as DNA degrades with age: a newborn cloned from a 27-year-old's cells will essentially start with 27-year-old DNA and cells.
 * James, the leader of the Auxiliary Animorphs, is crippled due to an accident rather than a genetic disease, so after demorphing from pidgeon he finds that he can walk again. Similarly, Loren's blindness is cured by morphing. Marco also heals a dog bite by morphing then demorphing.
 * Magic From Technology: Morphing in a nutshell, although it follows Magic A Is Magic A.
 * Magic Pants: Lampshaded very early on.
 * The Magnificent:
 * A complete list of Jake's nicknames: Big Jake, Fearless Leader, Jake the Mighty, Prince Jake, Jake the Yeerk-Killer (sometimes Big Jake the Yeerk-Killer, used mockingly), Jake the Ellimist's Tool, and (in the alternate timeline from Megamorphs #3) Supreme Leader.
 * And, of course, Marco's always calling Rachel "Xena: Warrior Princess".
 * Esplin 9466 the Abomination.
 * After the war, it's Aximili "of Earth".
 * Mama Bear: Both Loren and Eva qualify, but Naomi, for all her bossiness, thickheadedness and inflexibility, is the epitome of Mama Bear. In one instance, she attacks a grizzly bear that she thinks poses a threat to her daughters Jordan and Sara with a spice rack, and knowing her, probably would've won if it weren't for the fact that the bear was her eldest child.
 * As another troper noted elsewhere on the site, badassery is genetic in the Animorphs universe. Rachel's a Mama Bear to the rest of the kids, and Jake is the Papa Wolf.
 * Manipulative Bastard: Cassie, Marco, David, The Drode. But most of all, Jake, who becomes more and more manipulative as the series progresses.
 * Mauve Shirt: Most of the named "auxiliary Animorphs".
 * Meaningful Name: Sometimes obvious, sometimes not. According to Word of God, Lord of the Rings references are everywhere; Yeerk is a reference to "Yrch", the Elvish word for Orc, and Elfangor's and Aximili's names are references to elvish cities.
 * Meta Guy: Marco. The others often do it, but Marco makes it an art form.
 * Mercy Kill: Used disturbingly.
 * Middle Management Mook: Chapman.
 * Million-to-One Chance: At some point the reader may sit back and think, "Hey, wait a second. Yeerks are a race with insanely superior weapons. Not only that, but anyone can be a Controller. And this is a worldwide invasion. The heroes are six teenagers who live in a small town in California that can turn into animals? How the fuck can they stop the invasion? A bunch of animals couldn't beat the U.S. Army, never mind the Yeerks." This is lampshaded many, many times throughout the series, as the kids admit sometimes that the best they can do is slow down the Yeerks from time to time. They mostly lose battles and they agree that they'll never really be able to beat the Yeerks.
 * , due in large part the fact that the morphing technology is much more dangerous and versatile than it first appears. Rachel sums it up pretty well  when the kids are reflecting on how hard it is to kill an Animorph:
 * , due in large part the fact that the morphing technology is much more dangerous and versatile than it first appears. Rachel sums it up pretty well  when the kids are reflecting on how hard it is to kill an Animorph:

I was starting to see why Visser Three hated us so much."

"''Visser One: So. Still not dead.
 * The Mind Is a Plaything of The Body: Morphs come complete with the animal's instincts and desires. Some are useful, some can be ignored, some (ant, Taxxon) are horrifying.
 * The Minnesota Fats: Elfangor, but only from Ax's perspective. In fact, the main reason the Animorphs go to rescue Ax is because they feel an obligation to any Andalite because of Elfangor's kindness. From his own perspective, Elfangor is more of a Nice Job Breaking It, Hero.
 * Mister Muffykins: Euclid, Marco's stepmother's evil poodle.
 * Mix and Match Man: Ax's human form.
 * Mordor: The Yeerks' home planet. Also, in a way, the Yeerk pool.
 * Mook Promotion:
 * More Than Mind Control: There are voluntary Controllers, people who willingly let a Yeerk infest them. Many of them are simply so alone, so desperate to be part of something, that they're willing to give up their free will. The Sharing's main purpose is to find these sort of people and indoctrinate them.
 * Multiple Narrative Modes: They're primarily written in the first person, but switch into the third person at one point.
 * Mundane Utility: Includes getting keys off the pool floor and getting into concerts for free. Jake tries to forbid this, but he keeps failing miserably... especially when he wanted to go to both concerts.
 * My God, What Have I Done?: After the war, Jake is so guilty about and  that he is driven to clinical depression. As Marco puts it:
 * The whole series exemplifies this, to some extent. The kids agree that self-defense is justified, but the problem is when you kill a Controller, you don't just kill the Yeerk; you're also killing the host, who is completely aware but unable to stop the Yeerk. The kids debate during the entire series what is acceptable when it comes to self-preservation and exactly how far is too far. Initially the kids take a very narrowminded, black-and-white view - "We have the right to do anything we have to to win" - but as they mature and experience more in the war their moral lines become blurred to the point that they don't know the difference between right and wrong.
 * My Greatest Failure: Jake, whenever he recalls the David incident. Also the fact that Jake couldn't save Tobias from being trapped as a hawk.
 * Even moreso, the fact that he couldn't save or  from dying, not to mention the . Those two failures become to the entire focus of his personality for about five years.
 * Names to Run Away From Really Fast:
 * “The Abomination” is a name given to Esplin 9466 after he infests the Andalite Alloran. Granted, he fights with a sledgehammer, but do you really want to piss off someone with a sledgehammer of monstrous morphs from dozen of systems?
 * And from the Yeerks’ perspective, Jake is "Jake the Yeerk-Killer", and he earns the title.
 * Ax is kind of amused when he learns that Yeerks refer to his brother as "Beast Elfangor."
 * The Napoleon: The Helmacrons.
 * Narrative Profanity Filter: Being teenagers, and this being a very realistic series, the kids swear and flip each other off a lot. Depending on the "explicitness" of the word, it may or may not be directly written. "Crap", "damn" and "hell" are okay. Nothing else is explicitly mentioned, though the reader can guess the exact word most of the time.
 * Necessarily Evil: A lot of what the kids do. It causes them problems.
 * Never Found the Body
 * Never Say Die: Completely averted, and kinda lampshaded when Rachel initially thinks "I'm going to destroy ," but then she corrects herself: she's going to kill him. "Destroy" is a "weasel word" because it's vague and almost meaningless (the exact reason it's considered more family-friendly and often used in kids' fiction), whereas kill means kill.
 * When a bunch of Star Trek fans insist to help kids protect the Hork-Bajir's valley from a Yeerk onslaught all is splendid until Jake starts giving some last-minute orders, including "to move the wounded to safety but leave the killed lie." The father of the Trekkies family then asks timidly if by "killed" Jake meant "stunned or captured" and Jake replies that no, by "killed" he meant "killed to DEATH".
 * Nice Job Breaking It, Hero: Elfangor. Alloran's infestation by Visser Three was his fault.
 * That and Seerow being responsible for the Yeerks becoming a danger in the first place.
 * No Biochemical Barriers: Hork-Bajir can eat Earth bark and Andalites can eat Earth grass. Yeerks can interface with all sorts of alien nervous systems, suggesting a common signaling system. Also, it seems DNA is very common, forming the primary building block of almost all living organisms around the galaxy.
 * This could be justified by assuming that DNA is the only genetic molecule that works, so you can't have multicellular life without it.
 * Somewhat less probable is the fact that so many planets have life with cellular structures similar enough to animals for the process to work, though. It's not just DNA, or morphs would vary greatly in terms of weight and muscle tone (not to mention the clothing-and-hair thing), and the acquisition of the DNA (safely packaged in the nucleus of an animal cell) is a complicated question on its own. Let alone whatever nervous interface is used to trigger the morphing process based on visualization (although their ability to control morphs does suggest that the mind is at least partly independent of the brain in this universe). For the process to work, all species involved need improbably similar cell structures and embryology.
 * Ellimist did it?
 * Noble Savage: The Hork-Bajir before their war with the Yeerks.
 * No Celebrities Were Harmed: Jeremy Jason McCole (from #12) of the fictional TV series ‘’Power House’’, is totally not an expy of Home Improvement's Jonathan Taylor Thomas.
 * And yet, real celebrities' names were dropped all the time. Noah Wyle of ER was mentioned a lot, and book 17 gives us no less than seven real celebrity names at the Planet Hollywood concert. Cassie and Jake even use David Letterman as a code word when talking about David in an insecure phone conversation.
 * No Ending: Oh yeah. It approaches Mind Screw territory.
 * No Except Yes
 * No Mouth: Andalites.
 * No Name Given: All of the protagonists except Ax. In #23, Tobias' last name is transcribed as "______" in dialogue; however with the revelation that Elfangor as a human nothlit was Tobias' father, and that Elfangor went by the name "Alan Fangor" it is assumed that Tobias' last name as of or after the will reading at the end of #23 is Fangor. The revelation of Jake's last name (, which is probably also Rachel's) is used to highlight the seriousness of the new situation.
 * Actually Tobias' last name was more likely to be the last name of the man who "married" Loren after the Ellimist erased her memory of Elfangor. In TAC, it reads: "I saw Loren, and wrapped around her time line now was another human who would be her mate. I had been written out of her memory." (Tobias has the DNA of Loren and Elfangor's human Frolis Maneuver morph, but was raised as a baby by Loren and this other man.)
 * Non Sequitur Thud: Tobias crash-lands into a window and starts rambling about Clue at one point.
 * No One Gets Left Behind: Particularly memorably in #41 The Familiar.
 * No Paper Future: Used to comedic effect and to demonstrate Applegate's mild dislike of computers: Ax can't believe that books were invented before computers, because he finds them much quicker and easier to use. (He's also surprised that the telephone was invented before the chat room.)
 * No Sense of Humor: All of the Andalites, besides a few like Ax and Arbron.
 * Nostalgia Filter: An in-universe example: at the end of the series, Marco sees the years he spent fighting Yeerks as the "good old days". He remembers life-and-death battles as "cool, rock 'em sock 'em battles". He doesn't really seem to remember how much they scared the crap out of him at the time. But then, it's said that Marco has a much easier time adjusting to civilian life than the others, because he doesn't feel guilty about the things he's done.
 * Nothing Is the Same Anymore: After Visser Three's, the war quickly escalates and missions become increasingly important. This culminates in the discovery of the "Andalite bandits'" true identities. The seriousness of the kids' new situation is highlighted by the revelation of Jake's last name.
 * Not Quite Dead: After David leaves the barn, Jake sends Tobias to follow him. When Jake catches up,
 * While the Helmacrons and the kids are inside Marco's body, he morphs into a cockroach. The Helmacrons shoot Marco's heart, rendering him ostensibly dead.
 * Spoken word-for-word near the end of the final battle:

Jake: No, visser, not quite dead.''"

"Marco: I'm paranoid, sure. But that doesn't mean I don't have enemies."
 * Not So Different: There's some angsty speculation among the kids that taming and controlling their morphs' natural minds is the same as what the Yeerks do. Likewise the whole-sale slaughter of Yeerks, and the possible comparisons to terrorist attacks on civilians.
 * Crayak also does this with Rachel.
 * Also done with and the Pemalites, two alien species created by Crayak and the Ellimist. The  look like Always Chaotic Evil who kill everything in their path and the Pemalites are insanely pacifistic, but the two races, thanks to how they were designed,.
 * Not Wearing Tights: Kinda.
 * Number Two: Marco fits the traditional role of The Lancer, but Tobias seems to fit this role. Jake usually appoints him leader of the Marco-Tobias-Ax sub-team, which ended up carrying the end of the war.
 * Odd Friendship: Tobias and Ax.
 * Official Couple: Jake and Cassie, Rachel and Tobias.
 * Off With His Head: Visser Three's preferred method of execution, though he's a fan of torture as well.
 * Oh Crap: A couple times, but most notably in the second-last and last books. First, when, and second, when
 * Oh God, Did She Just Hear That?: The Leerans are fully-capable mind readers. As are, naturally, the Animorphs when they morph Leerans. Their first conversation in Leeran morph is... awkward.
 * "Um, I'd just like you all to know," Marco said loudly, "that whatever thoughts you may be hearing are completely made up. They're not real."
 * One-Winged Angel: Technically all of the "battle forms" count, though Visser Three gets to do a classic example at least once every few books.
 * Online Alias: Mostly features the "modern" kind: YeerKiller9, Gump8293, Bball24, etc. But it also has some more hacker-like ones, like "Govikes" and "YrkH8er". The Ketrans use gaming names as well.
 * Open Says Me
 * Opt Out: Right before the final battle, a lot of the Auxiliary Animorphs decide that they want to sit it out, due to the fact that their friend Ray was recently killed. Jake doesn't really care and makes them go anyway. ("We didn't give them morphing power so they could have fun flying around. This is when we need them. All of them. You're their leader, James, so lead.")
 * Opposites Attract: Rachel and Cassie.
 * Our Centaurs Are Different: Andalites are blue centaurs with scorpion tails and stalk eyes. In one book, a TV show gets a few seconds of an Andalite on film and wonders if it proof that centaurs exist.
 * Ordinary High School Student: All of them (excluding Ax of course). And Tobias, after the first book.
 * Organic Technology
 * Orifice Invasion: The Yeerks. In the ear.
 * Other Me Annoys Me
 * Out Gambitted: Visser One's plan worked well. Tom's worked even better. Jake's worked best of all.
 * Overly Long Name: The Ellimist's real name is Azure Level, Seven Spar, Extension Two, Down-Messenger Forty-One. Ketrans' names are basically their address—which is why they tend to call each other by their chosen names or gaming handles.
 * Painful Transformation: Actually, it's specifically mentioned that while there's no actual pain, it definitely feels like there should be.
 * Panthera Awesome: Big cats make good battle morphs. Jake's main morph is a tiger, while David and James both had lion morphs. There were also times when the whole group morphed jaguars and cheetahs. Hell, even Tom's favourite battle morph is the jaguar.
 * Parent With New Paramour: Marco's dad eventually marries Nora Robbinette, his son's math teacher.
 * Parental Abandonment: Tobias' dad is dead, the other is Tobias is "raised" by his aunt and uncle, neither of which want anything to do with him.
 * The Password Is Always Swordfish: The access code for the Pemalite spaceship is '6'. That's it. Just '6'. It's justified, in that the Pemalites were incredibly peaceful and trusting. They are also all dead; and the Yeerks cracked the code in about a second.
 * Path of Inspiration: The Sharing.
 * Patrick Stewart Speech
 * Pay Evil Unto Evil:
 * Also, Marco isn't very good at hiding the fact that he takes pleasure from killing Yeerks. In #19, he tells Cassie, "You don't make peace with parasites. You don't turn them around. You bury them."
 * It eventually subsides, though, as part of Marco's Character Development; over the course of the series he becomes much less emotional, which makes him a more effective strategist.
 * Percussive Prevention: When Ax realizes that the only way to in book #46 is to, Jake, naturally, objects. Ax knows he can't force Jake to have any responsibility for it, so he calmly knocks Jake out.
 * Perfect Pacifist People: The Pemalites, a ridiculously peaceful race who were completely obliterated by a more militaristic species. Tragically, their incredible technology could have been converted into weapons that would easily destroy their opponent, but as a species they couldn't bear to do so.
 * There's also the Hork-Bajir, who while not as advanced, were also totally peaceful, and were enslaved when they caught the attention of a more aggressive race. Notable in that both of these species were created artificially, and designed to be non-violent by their creators. The series seems to give the impression that while being a pacifist sounds great, in reality it isn't a good survival tactic.
 * Phlebotinum Breakdown: Happened a couple of times with Body Horror-riffic results. Rachel suffered a case of Involuntary Shapeshifting, turning into crocodiles, ants, and elephants at inconvenient times. Marco got it even worse, turning into a series of BiologicalMashups. (Dude. Osprey-Lobster. Trout-Gorilla. Neither of which could breathe. And, of course, the mighty poo-bear! [Poodle-Polar Bear.])
 * Planet of Hats: The Iskoort.
 * Playful Dolphin: As you'd expect, the dolphin morph is pretty playful..
 * Plucky Girl: Loren. She's Rachel Lite.
 * Population Control: Mentioned for the Andalites in The Andalite Chronicles.
 * Powder Trail: The villain uses this to blow a hole in HMS Victory in Elfangor's Secret.
 * Power At a Price: To quote Jake: "The power made us responsible, see. Without the power the knowledge would have just been a worm of fear eating up our insides. Bad enough. But it was the power that turned fear into obligation, that laid the weight on our unready shoulders ... Power enough to win? No. Power enough to fight? Ah, yes. Just enough, little Jake, here is just enough power to imprison you in a cage of duty, to make you fight..."
 * Power Nullifier: The anti-morphing ray.
 * Power of Friendship: Corrupted by the imitation abilities of the Yeerks.
 * But Marco and Jake's friendship is a theme in the series. Jake and Marco have been best friends since they were old enough to talk, and are immensely loyal to each other. It's said that Marco only initially joined the war effort because of his loyalty to Jake, and throughout the series that loyalty is the source of many crowning moments of heartwarming. Marco is the only one who never criticizes Jake when it's apparent that he's already under a lot of stress, notable because normally 99% of criticisms come from Marco.
 * Made even more heartwarming by the fact that Jake is the only person Marco really respects. Everyone else just brings out Marco's sarcastic Deadpan Snarker mockery.
 * Power Trio: Marco, Ax, and Tobias were often sent alone on missions, especially near the end of the war. Ax and Marco switched off, but Tobias was always Ego/Kirk.
 * Power Parasite: Following this trope literally, Yeerks use other creatures as hosts for their specific abilities.
 * Praetorian Guard:
 * Visser Three's Blue Band Guard. Named after the blue armbands they wear.
 * Also, the Orff, a race of aliens who act as security agents to the Council of Thirteen.
 * Pragmatic Villainy: Subverted with Visser One.
 * Pretty Boy: Ax, in his androgynous male human morph, which is made of DNA from Rachel, Cassie, Jake, and Marco.
 * Properly Paranoid: All the kids to some extent, but Marco takes it really really far, mostly because he's the most afraid of dying.
 * Pretty Boy: Ax, in his androgynous male human morph, which is made of DNA from Rachel, Cassie, Jake, and Marco.
 * Properly Paranoid: All the kids to some extent, but Marco takes it really really far, mostly because he's the most afraid of dying.

"Jake: CATCH! THAT! BUTTERFLY!"
 * Proud Warrior Race Guy: Ax, though it's explicitly said that Andalites aren't really a warrior race. Andalites are supposed to love peace, and spending time with their families, and communing with nature, and so forth. But Andalite warriors, while pretending to love those things, are really only interested in fighting for the glory of the Andalite people.
 * Proud Merchant Race: The Iskoort.
 * Punctuated for Emphasis:

"Jake: Ax?
 * Puppeteer Parasite: The Yeerks.
 * The Purge: Late in the series, a massive campaign to reorganize the Yeerk Empire begins, headed by Visser Three..
 * Psychic Powers: Leerans, Andalites, the Ellimist, Crayak...
 * Andalites are not actually psychic. Thought-speech seems to be a physically measurable phenomenon (the Nisk had thought-speak detectors; Andalites have thought-speak microphones) present in the brains of some species that allows them to broadcast thoughts. Even more supported in that only linguistic information can be transmitted, suggesting that the transmitter is located in the language centers of their brains. Apparently absolutely any brain can act as a receiver without any specialized neural structures.
 * Further supported while simultaneously providing an explanation for why the morphing technology grants thought-speech to those in morph. If an Andalite's thought-speech transmitter was a physical structure in their brains, they would lose it during a morph and thus be unable to thought-speak unless the morphing technology included that feature.
 * Psychic Static: John Berryman, Jr. thinks Henry V at Visser Four, so much so that the very first thing he does when he finds the Time Matrix is try to change the result of the Battle of Agincourt so that Shakespeare would never be inspired to write it.
 * Psycho for Hire: Taylor.
 * Punny Name: "Animorphs", a portmanteau of Animal Morphers, was a name originally devised as a joke by Marco, reminiscent of the Justice League and other superhero team names. The kids more or less jokingly adopt the name, but refer to themselves as "the Resistance" or something similar to outsiders. By the end of the war, their enemies begin seriously calling them Animorphs, and they begin calling themselves Animorphs seriously as well.
 * Put Off Their Food: In The Android, Marco's parents try to serve him chicken for dinner after he was nearly killed by a bird while in spider morph. Marco opts out.
 * The Quisling: Chapman in The Andalite Chronicles, Taylor.
 * Quit Your Whining: Jake does this to Marco in Animorphs #35, helping him to recover from his Shapeshift Crisis. Marco also does this to Rachel in #37 (in what many people see as a Crowning Moment of Awesome) snapping her out of Heroic BSOD.
 * Ragtag Bunch of Misfits: Subverted; while a bunch of kids aren't what you'd call a stellar planetary defense army, they turn out to be remarkably good at it, especially Marco.
 * Gets deconstructed in #38. The Andalites send an expendable team of military misfits to earth on a shadowy secret mission that involves manipulating the Animorphs, only to be clearly outclassed by the (by now) extremely disciplined and battle-hardened Animorphs. Comes complete with a Reason You Suck Speech / Screw You Elves to the Andalite leader that becomes a mini-CMOA for Jake.
 * Reality Ensues:.
 * Reality Warper: The Ellimist.
 * Reasonable Authority Figure: The governor of California. No, not Arnold Schwarzenegger.
 * Recruit Teenagers With Attitude: Deconstructed. The teens win the war, but they suffer some pretty serious psychological damage in the process.
 * Recycled in Space: The book The Hork-Bajir Chronicles is not dissimilar to Pocahontas, gender-flipped, IN SPACE.
 * Redshirt Army: The actual US Army, as well as the, in the last battle. Toby's Hork-Bajir army get killed a lot, too, near the end of the series.
 * Reluctant Warrior: Cassie
 * The Remnant: Referenced..
 * Ret Gone:
 * Revenge By Proxy:
 * See Pay Evil Unto Evil.
 * Rewarded As a Traitor Deserves: is a subversion, as
 * Played straight with
 * And that fucking asshole Chapman. As a teenager, he's kidnapped by the Skrit Na and rescued by Elfangor, Arbron and Alloran. When he meets the Yeerks, he tells them all about Earth (of which they were previously unaware) which essentially leads to the entire fucking invasion. Chapman's memory is erased, but then many years later, when the Yeerks arrive, Chapman is turned into a Controller. What's funny is that he doesn't realize that he was the architect of his own enslavement.
 * But then there's book 2, where you found out that he and his wife are willing to fight for control just long enough to strangle themselves rather than let their daughter be taken over.
 * Richard Nixon the Used Car Salesman: Hitler is implied to be this in Elfangor's Secret.
 * Robot Buddy: Erek King. But
 * Robotic Reveal: Suspicions are aroused when the Animorphs-as-dogs realize that Erek has no scent, but it's not until Erek is hit by a truck and the Animorphs get a good look at him through the eyes of a wolf spider that they realize that Erek is an android.
 * Rock Beats Laser: Very much so
 * Rooftop Confrontation
 * Royals Who Actually Do Something: In Andalite society, "Prince" is a military rank... So it stands to reason that princes would actually do some fighting.
 * Rubber Band History: Elfangor's Secret opens in the world where Visser Four's time travel plans went on unchallenged. Jake calls himself "Supreme Leader" and is considering turning Cassie in for possibly opposing the genocide in South America. Everyone, Cassie included, owns a slave. Melissa has replaced Rachel, who's in a reeducation camp. Oh, and Pong has just debuted, and cable television is nowhere to be found—there’s only one heavily censored channel.
 * Rubber Forehead Aliens: Oh so very averted. Not only do all the other alien races look nothing like humans, but it turns out that humans are the only alien civilization in the universe that walks upright on two legs.
 * Well, Hork-Bajir have two legs, but they have their tails for balance.
 * Word of God is that Applegate originally intended to use Rubber Forehead Aliens just in case the series got a Live Action Adaptation. Then Scholastic rejected the idea and told Applegate to be more creative. So she did and made the aliens damn-near IMPOSSIBLE to adapt to live-action (at the time). Then the TV series was made and we all know how that turned out.
 * Running Gag:
 * Running Gag:

Ax: Yes, Prince Jake?

Jake: Don't call me prince.

Ax: Yes, Prince Jake."

"Jake: Andalites are very fast, those snakes are faster. One move from your boys and they will die... Now we stop playing games, you're not the Andalite fleet, and I'm not going to snap a salute and say 'Yes Sir!' We deal as equals. Which, to be honest, is generous of us under the circumstances.
 * Jake eventually lampshades it as a running gag between them. He also specifically notes that if he doesn't say "Don't call me prince", it's a sign of how serious the situation is.
 * Sad Clown: Marco.
 * Samaritan Syndrome: Marco, of all people. Though all the kids have it to some degree.
 * Sapient Cetaceans: Cassie has a minor crisis because she's not sure if it's right to take a dolphin's DNA or control its mind; one of their rules is that the Animorphs never morph a sapient creature without its permission, or unless it's an urgent emergency. Whether or not they're truly sapient is never quite settled (although whales just barely are, according to the Drode), but they are capable of a kind of telepathic communication with whales ("great ones;" the dolphins are the "little ones."), and Cassie firmly believes they have souls. Everyone loves the dolphin morph, because they're so happy and carefree.
 * Screw the Rules, I Have Supernatural Powers : David
 * Screw This, I'm Outta Here: Marco, until he discovers that . Cassie, temporarily, on more than one occasion.
 * Screw You Elves: From #38:

Gonrod: I command here. Am I clear on that?

Jake: No, sir. This is Earth. This is a human planet. We are not the Hork-Bajir, we know how you 'rescued' them. As long as you're on earth, you'll get along with us. Am I clear on that?"

"Marco: Anyway, she tells me, 'Some kid went crazy and ate an entire pan of cinnamon buns.' Now, who, I ask you all, who do we know who would eat an entire pan of cinnamon buns?"
 * Sealed Room in The Middle of Nowhere: The Animorphs condemn David to one, leaving him on a rocky deserted island in the middle of the ocean.
 * Secret Keeper: The Animorphs themselves are Secret Keepers for the existence of the Chee, the location of the free Hork-Bajir, and the fact that Aftran and Illim/Mr. Tidwell are members of the Yeerk Peace Movement, while these factions are all Secret Keepers for the Animorphs' identities and the fact that they're mostly human. This becomes a huge problem when Visser Three captures and intends to interrogate (read: torture) Aftran. Later,
 * Sense Freak: Ax in human morph, as Andalites are mouthless ("Cinnamon BUNZAH!!!").
 * Set Right What Once Went Wrong: Elfangor's Secret, although it was more like "re-set what was originally kinda going okay but this one guy fucked up and the Ellimist and Crayak are panicking now."
 * Shape Shifter Mashup : Marco in The Proposal. He morphs a osprey/lobster mix, a spider/skunk mix and a polar bear/poodle mix, respectively.
 * Might also be said of anyone who uses the Frolis maneuver to create a morph of the DNA of several individuals of a species combined.
 * Shapeshifter Mode Lock: More than two hours in a morph traps you in that body.
 * Shapeshifter Showdown: Both the Animorphs and Visser Three have shapeshifting powers, so these are common enough. The most extreme example is probably in #48, where Crayak pits Rachel and Visser Three against each other in a gladiatorial battle and they both strategically change forms constantly throughout the fight.
 * Sharing a Body: Controllers (Yeerks and their hosts). Also Cassie and Aldrea in #42
 * Sheep in Wolf's Clothing: Marco pretending to be a Controller.
 * Shell Shocked Senior:, by the time he's eighteen.
 * Shoot the Messenger: Visser Three, all the goddamn time.
 * Shoot Your Mate: Visser Three tries to get Visser One to.
 * Shout Out:
 * Amusingly enough, the name of the mind-controlling slugs is an anagram of the middle name of Senator John Yerkes Iselin from The Manchurian Candidate. However, the Yeerks in Animorphs take their name from JRR Tolkien's Sindarin Elvish word for Orcs, yrch.
 * Also many, many more subtle and insignificant ones, such as the six dolphins named after the main characters of Friends in book #4.
 * Generally, Applegate references her favorite things often in the series: Star Trek, the Rolling Stones, the Ford Mustang, Dr. Pepper, et cetera.
 * Shown Their Work:
 * In amongst all the alien warfare, there are detailed descriptions of about a hundred different animal species. Applegate clearly researched a lot of the morphs and went to great lengths to detail them accurately.
 * Applegate also dabbles in military history and literature from time to time.
 * When turning into a bee, Marco describes a color so unbelievably intense humans can't see it, but bees can. He's seeing ultraviolet, which many flowers use to attract bees.
 * Silly Rabbit, Idealism Is for Kids
 * Sixth Ranger: Ax. And then a Seventh Ranger, David. . James and the Auxiliary Animorphs count as eighth rangers.
 * Sixth Ranger Traitor:
 * Skippy Rules: The Law of Seerow's Kindness.
 * Slap Slap Kiss: Almost completely averted. Rachel and Marco had a very antagonistic relationship, but she and Tobias were pretty much an item from day one. Not completely, because Marco makes several comments indicating he might have a mild crush on Rachel (although his perception that she's certifiably insane balances it out), "Nice Rachel" says flat-out that she would probably go out with Marco if he asked her, and in the What If / Wonderful Life book "Back to Before", they actually did go out.
 * Sliding Scale of Anti-Heroes: Although the Animorphs spend most of the series somewhere in between type 1 and type 2, dives straight into type 4 during the last 2 books.
 * Sliding Scale of Idealism Versus Cynicism: The series starts out on the idealistic side, and ends more on the cynical side. The gist of the series is pretty much that the universe is a violent, dangerous and evil place, and things are bad all over, but we should try to do the right thing as often as we can anyway. To quote Jake: "It was a stupid, naive, idealistic and childish decision. But I wouldn't want to live in a world where we didn't try the stupid, naive, idealistic and childish thing sometimes."
 * Slumber Party Ploy: Used occasionally.
 * Smarter Than You Look: You don't want to mistake Rachel for a ditz.
 * The Smart Guy: Ax, because he's an Andalite and therefore knows a lot more about science. But Marco's smarter than Ax is in terms of actual intelligence.
 * Smug Snake:
 * Marco. He's the only guy that Jake will let get away with constantly insulting him.
 * You don't see it much, but Tom.
 * David.
 * Soapbox Sadie: Cassie often voices her opinions on issues she considers morally compromising. The other characters (and the readers) sometimes get annoyed with this.
 * Somebody Else's Problem: Initially, the kids see the Yeerk war as strictly between the Andalites and the Yeerks, which is why Marco is so against getting involved. However, when Jake learns Tom is a Controller, the kids realize that the stakes are much closer to home than previously thought. By the end of the series, the kids have lost their faith in the erstwhile Andalite reinforcements, and have concluded that it's all up to them.
 * Space Is an Ocean
 * Spike Shooter: One of Visser Three's morphs can do this.
 * Spikes of Villainy: The kids have a hard time accepting the fact that unhosted Hork-Bajir are, in actuality, good guys, due to the dangerous-looking blades the cover the Hork-Bajir figure.
 * Spock Speak: Ax. The author is very particular about it; it is carefully stated that Ax picks up actions like nodding his head and shrugging his shoulders from talking to the kids a lot.
 * Spy Speak: Periodically lampshaded by Marco, but mostly used in telephone conversations to arrange meetings.
 * Stable Time Loop: In In the Time of Dinosaurs, the Animorphs are sent back to the last days of the Cretaceous. They ally with good aliens, the Mercora, against bad aliens, the Nesk, and steal a nuclear explosive from the Nesk to attempt to return home. The defeated Nesk leave the planet but send the Mercora a parting gift,
 * Star-Crossed Lovers: Rachel and Tobias. She's a beautiful, smart, independent, funny and spirited suburban teenage hottie. He's a bird.
 * Starfish Character: #32, The Separation, in which Rachel is split into Mean Rachel and Nice Rachel. Everyone hates them both. And it involves an actual starfish too!
 * Starfish Aliens: Most aliens shown are such. Yeerks (parasitic mind-controlling slugs that feed off of radiation) Taxxons (giant centipedes with a crippling hunger that will eat themselves if they get wounded) and Andalites (Telepathic centaurs who eat out of their hooves) being the strangest, with everything else not far behind.
 * The Starscream: Visser Three to Visser One.
 * Stay With Me Until I Die: Gafinilan and Mertil.
 * Stock Yuck: Broccoli comes from aliens planting it here in the Cretaceous Period.
 * Story Arc: The series can neatly be divided up into a couple story arcs. The first arc concerns itself with the development of the children into soldiers and explanations about morphing, the Yeerk invasion, et cetera. The second arc concerns itself with the day-to-day missions, and is cut in half by what you could call Story Arc 2.5, which concerns itself with the seventh Animorph, David. The third story arc deals with the escalation of the war and the reorganization of the Yeerk Empire - the execution of Visser One, Visser Three's promotion, Operation 9366, et cetera. The final story arc begins when the Yeerks discover the kids' identities.
 * Strange Bedfellows: Rarely with Visser Three, occasionally with Visser One.
 * Stranger in A Familiar Land:
 * Rachel, in #48, has an internal monologue about how she feels isolated and apart even in a crowded school hallway.
 * Jake, who can't relate to anyone after the war because they don't know what he's been through.
 * Also, Tobias, as he's a hawk, and he has no more connection to humanity.
 * And Ax. The things he's learned on Earth - the willingness to justify your actions to your subordinates, the acceptance of vecols as members of society - cause him to be seen as strange to other Andalites. Although, by this time, he's enough of a legendary war hero to get away with it.
 * Subspace Ansible: Z-Space communication.
 * Sufficiently Advanced Aliens: The Ellimist and Crayak.
 * Superior Species:
 * Yeerks feel this way towards humans to some extent, but some can empathize with them (most Yeerks liken what they do to humans to what humans do to cows or pigs, but some realize that they steal others' bodies for themselves, and some realize that this is wrong)...
 * Andalites are repeatedly characterized as arrogant, and see humans are curiosities at best and expendable inferiors at worst. (This provides an interesting twist: Jake and the others are waiting for a good part of the series for Andalites to save them, but Andalites don't give a damn about humans.)
 * Subverted in the last book. It's revealed that it's really only the Andalite military that's like this. Andalite civilians are much more agreeable and get along with humans just fine.
 * Survivor Guilt
 * Super Team: The Animorphs, of course.
 * Supporting Leader: General Doubleday.
 * The Symbiote: The Iskoort. The "Yoort" descended from Ancient Astronaut Yeerks. They once went on a galactic conquest like their cousins, but they eventually realized the futility of it and made the conscious decision to modify their entire race as symbiotes with an artificially created lifeform, the "Isk".
 * Take a Third Option:
 * David took one too.
 * Take That:
 * #48, on describing the prospect of dramatizing the morphing process Rachel lists a handful of studios who she's convinced "wouldn't get it right." She explicitly lists Nickelodeon, who produced the Animorphs TV series, which KA Applegate has been vocal in her distaste for.
 * Also, the Andalites were originally supposed to resemble stereotypical Grey aliens. Scholastic vetoed the original design and asked Applegate to be a little more "creative" so that if an Animorphs TV series was ever produced, they would have an interesting looking alien race to showcase. She then went ahead and made them as unnecessarily complex as possible--out of spite--to the point where they proved virtually impossible to properly dramatize when said TV series finally came into fruition. Take that, indeed.
 * Team Dad: Jake, who gets teased about it.
 * Team Mom: Cassie sort of fits this role. She gives emotional support to the others whether they want it or not.
 * Technical Pacifist: The Chee in general, Erek in particular: Cassie may also qualify.
 * Technology Marches On: #16 The Warning, the "Internet is weird" book.
 * Telepathic Spacemen: The Andalites and anyone who uses their morphing technology.
 * The "The" Title: Done with nearly every book in the series, excluding Visser, Megamorphs 3: Elfangor's Secret, and Megamorphs 4: Back to Before. Megamorphs 2 does feature "the" in the title, although it's not the first word: In the Time of the Dinosaurs.
 * Time Dissonance: Father (and, afterward, the Ellimist).
 * There Are No Therapists: Though Cassie tries.
 * They Call Me Mister Tibbs: As an aristh, Ax needs a prince. Jake is that prince, much to his embarrassment.
 * Three Laws Compliant: Some laws are deconstructed, some are averted: The Chee comply with the Third and Zeroth Laws, but their creators, the Pemalites, took the First Law to the logical extreme: no violence, period. As for the Second Law:
 * Think in Text: The use of punctuation,, to indicate thought-speech.
 * This Is Reality: The Animorphs are fond of either comparing their acts to superheroes' or of pointing out that said superheroes aren't real.
 * Time Abyss: The Chee
 * Time Machine: The Time Matrix. Not really a machine, per se, but all we really know is that it was created by the Ellimist.
 * Time Stands Still: The Ellimist.
 * Time Travel : Many times.
 * Tricking the Shapeshifter: Combined with enforced Shapeshifter Mode Lock to defeat.
 * Trademark Favorite Food: Ax and his intense, intense LOVE for cinnamon buns. He even keeps a picture of one in his makeshift home.


 * Tonight Someone Dies: The cover quote of the final book is It began with six. It will end with five. Oh, NOW they get it right! Sort of. It REALLY began with five.
 * Too Many Halves: Ax -- and by extension the Andalite race in general -- is once described as half blue deer, half centaur, and half scorpion. Then the narrator Lampshades it by saying they realize that it's too many halves.
 * Totally Radical: Invoked by one of the characters. One comments that they'd "bet dollars to donuts" on something and another comments "Something your grandmother used to say?"
 * Touched By Vorlons:
 * The Escafil Device (blue box), which gives normal beings the power to morph after contact with it.
 * The Andalites themselves got a big speed boost to their evolutionary process when Toomin went native with them in The Ellimist Chronicles.
 * Tragic Dream: Jake's weakness is his sense of responsibility: As long as he can, he feels he's got to at least try to save his brother Tom. Jake's entire motivation, right from the beginning, is to free his brother. As the years go by this becomes less and less likely. And it all culminates in the worst possible way:
 * Tragic Hero: Jake.
 * Training the Peaceful Villagers: The Hork-Bajir, both in The Hork-Bajir Chronicles and The Resistance.
 * Transformation Trauma: The books go on and on about how Morphing isn't nice to look at, often describing the process in excruciating detail.
 * Translator Microbes: All members of the Andalite military have translator chips implanted in their brains.
 * Trickster: The Drode.
 * Troubling Unchildlike Behavior: They're kids. They kill people.
 * True Companions: Most obviously shown at the end of the series, when the kids see as a moral obligation.

""I command this ship," Efflit 1318 explained, "but I serve at the pleasure of The One Who Is Many. The One Who Is All. We are not alone, Rakich-Four-Six-Nine-One. We are not this ship alone. We are the seeds of a new Empire that will far outshine the old, an Empire that will flourish under the leadership and wisdom of The One.""
 * Two Act Structure: The secretive guerilla war, and the final story arc.
 * Two of Your Earth Minutes: A Running Gag with Ax.
 * Universal Driver's License: Marco. See I Know Mortal Kombat.
 * The Unmasqued World: The last book..
 * Unobtainium: Ramonite, which Andalite (and thus, also Yeerk) ships were made of, can turn opaque or transparent or be completely reshaped to form open doors, all through computer commands.
 * Unusual Euphemism: The Hork-Bajir biology causes them to lapse into their native language, which is used to get cursing into the books. Context makes it clear.
 * Unusually Uninteresting Sight: Among many others, the commercial scene in the third book.
 * Unreliable Narrator: Most of the characters, especially early on, aren't capable of recognizing their own character flaws, and their narration is reflective of this. Furthermore, sometimes the kids just straight-up lie about things - see Literary Agent Hypothesis. For instance, in the David trilogy, Jake says it's been a couple months since Elfangor's crash. Dialogue, however, hints that the story arc takes place much later, and it's confirmed late in the series that the David trilogy takes place maybe two years after the crash.
 * Unresolved Sexual Tension: Jake and Cassie for a good half of the series, before they make their mutual crush public. Also, Tobias and Rachel - it's the entire focus of their relationship, really, because Tobias is a bird.
 * Vein O Vision: Howlers use it to see weak points.
 * Verbal Tic: David has a tendency to say the name of the person he's talking to several times in a single conversation, usually when he's trying to be threatening. In one occasion in The Solution, he says Rachel's name six times in one page.
 * Vetinari Job Security: In which Mr. Responsible Jake has to leave for a week and Rachel, who is, to put it diplomatically, something of a violence junkie, is made temporary leader. The end result is Cassie getting captured and dangerously close to the 2-hour limit.
 * Viewer Friendly Interface: The Pemalite ship.
 * The Virus: Yeerks.
 * Vitriolic Best Buds: Marco and Jake, who are best friends despite the fact that they argue more often than not.
 * Villain Ball: Visser Three, first by, and by
 * And Chapman, who inadvertently caused his own infestation thirty years in advance.
 * Villain of the Week: Sometimes. Notable examples include: The Helmacrons, The Nartec, The Howlers, the Smug Super Yeerk known only as The Inspector, and Taylor.
 * Violence Is the Only Option: Deconstructed. Is violence really the only option? At first glance, it seems that it is: Yeerks are stealing bodies by force and the kids have to stop them. But as the kids learn, Yeerks need bodies to properly live, and it's possible for the Yeerk and the host to have a symbiotic relationship. The problem is most hosts would resist infestation, which necessitates taking hosts by force. Cassie often tries to convince Yeerks that symbiotism is the best solution - and it works sometimes.
 * Voluntary Shapeshifting: Lots of Shapeshifting Tropes too, eh?
 * Wagon Train to The Stars: The journey that Marco, Santorelli, Menderash, Jeanette, Tobias and Jake take aboard the Rachel to find the Blade ship was, at least according to Marco. We never get the details of their adventures, though.
 * Wake Up, Go to School, Save The World: Not nearly as much as one would think, but most prominent in #22. By the end of the series, fighting Yeerks has been a full-time, round the clock job, so the kids rarely (if ever) go to class, instead getting the Chee to fill in for them.
 * The Walls Are Closing In: In "The Separation", Visser Three used a moving wall because he thought the group were Andalites, who hate enclosed spaces.
 * The War Room: Where Jake first meets General Doubleday. Jake notes that it seems an awful like what you'd see in a movie; old guys chomping cigars, guys in suits and a big map (that has his hometown crossed out, ).
 * War Is Hell: The Aesop of the series, though not quite that simple, as it incorperates elements of What Is Evil?, Black and Gray Morality, and Child Soldiers.
 * Warm Bloodbags Are Everywhere: The Taxxons. Mostly seen through the eyes of Arbron, and Tobias when he morphs Taxxon.
 * Wasn't That Fun: Marco does this all the time.
 * Memorably played straight and subverted in Book #30. Marco, Tobias and Ax go sliding down several stories worth of staircase bannister in cockroach form on their bellies at warp speed. When they get off, they exult in how awesome it was... just before agreeing to never, ever do that again.
 * We Are Team Cannon Fodder: The Auxiliary Animorphs, and the U.S. Army. In fact, that was the whole point.
 * We Are As Mayflies: The guerilla war between the Animorphs and the Yeerk Empire lasted three years and shaped the fates and lives of thousands of sapient creatures. The larger war between the Andalites and Yeerks was on a scale even larger. But in the end, the entire conflict was only a blip so small as to be unnoticeable when it came to the war between Ellimist and Crayak. The kids' war lasted three years, the war between Ellimist and Crayak lasted hundreds of millions or even billions of years, one that continues even after the Yeerk Empire is destroyed. If one looks at the series as a battle between good and evil, absolutely nothing was accomplished. What's one Yeerk Empire to Crayak?
 * It's implied that the war is more critical than it seems, for reasons that will only be clear to the mortals of the galaxy a century or two down the line.
 * True, considering how much the Yeerk war influenced the budding, new conflict between humans, Andalites, Yeerks, Kelbrid and The One:

"Marco: It's got to be kids. Adults are too reality-bound. It's too hard for them to suspend disbelief for all this weirdness, even when it hits them square in the face."
 * Weirdness Censor: The reason that, when discussing who to recruit for the Auxiliary Animorphs, the kids decide that Adults Are Useless.

"Aftran: What choice do we have? Back to the Yeerk pools? Back to our home planet, with Andalite Dome ships in orbit above us, waiting for one of us to rise from the sludge, then blow us apart? Leave the universe to the almighty Andalites and the species they happen to like?"
 * Weird Trade Union: Book #26 has the Iskoort, whose entire society is apparently composed of Weird Trade Unions (see trope page for specific examples).
 * What Happened to The Mouse?: Ax never really does avenge his brother's death, does he?
 * There's a fair amount of these, actually: We never hear very much about Tobias, Cassie, and Jake's parents following the war, the being that caused Jake to see the alternate future in book #41, the other two andalites who survived the initial battle in Earth's orbit, and whatever happened to Chapman and his family?
 * The Return actually deals with exactly this in a somewhat literal form:
 * The aliens behind Book #41 are implied to not be the Ellimist or Crayak; but they neither revealed or mentioned again.
 * What If: Back to Before: What if the Animorphs never met Elfangor? Things still would have blown up, that's what. Just faster and with even more angst.
 * Also: What if the kids gave up? Earth becomes a Yeerk-infested hell, as you might expect, with the kids themselves becoming Controllers.
 * What if Jake became too ruthless and cocky? In #41, Jake, in the heat of battle, leaves Marco and Rachel to fend for themselves, in order to save the rest of the team. The continuation of this mindset is shown in the far future: Tom suspected Jake of being an "Andalite bandit", and turned him into a Controller. Ax, Marco, and Cassie are taken, Rachel is gravely wounded in the ensuing battle, and Tobias escapes. Marco becomes host to Visser Two, and Ax becomes a key player in the attack on his homeworld. Cassie's Yeerk, Niss, joins the Evolutionist Front, a terrorist group dedicated to the creation of artificial hosts, led by Tobias, who permanently morphs Ax. But even Cassie and Tobias aren't good guys: Cassie becomes ruthless, cynical and practically evil ("In a war, Jake, anything is justified."), and Tobias is completely willing to let Cassie die to score a victory ("Save one, or save many? The choice wasn't so hard at the Ragskin building, when you left Marco and Rachel to save themselves.")
 * What Is Evil?: Frequently brought up. Yeerks need hosts, hosts need their freedom. Somebody has to lose. Are Yeerks evil because they fulfill their natural function? If that's the case, are humans evil for killing animals for meat?
 * What Measure Is a Mook?: Very low, until it's clear that the Yeerk-infected aliens are people too.
 * What Measure Is a Non-Cute?: At the start of the series, it seems this was, with a slug-like Yeerks as the bad guys and the mammal-like Andalites as the good guys. As per usual for Animorphs, this doesn't stick.
 * What Measure Is a Non-Cute?: At the start of the series, it seems this was, with a slug-like Yeerks as the bad guys and the mammal-like Andalites as the good guys. As per usual for Animorphs, this doesn't stick.

"[[spoiler:''Erek: I see. He feels guilty.
 * What Measure Is a Non-Human?: Deconstructed. The Animorphs are less hesitant to kill when fighting Taxxons or Hork-Bajir rather than human-controllers. Visser One notices the discrepancy in human-controller casualties, confirming her suspicions that the "Andalite Bandits" are actually humans. Whoops.
 * What the Hell, Hero?: Fairly common, though usually just over the line. Rachel plays it well, Marco recognizes the need.
 * A slightly less serious example, but still in and of itself a What the Hell, Hero? moment is when Tobias is at a dance with Rachel, in his human morph, and she tries to trap him in it so they can have a normal relationship. Tobias doesn't exactly call her out on it, because part of him isn't entirely convinced she wasn't right.
 * Weapon of Mass Destruction: Ax is amused by "primitive" human nuclear weapons, and while humans haven't figured out cold fusion yet, Ax claims Andalites only use it to power children's toys.
 * We Are Everywhere
 * We Come in Peace, Shoot To Kill
 * Wham Novel: Novel #23: The Pretender.
 * Turns into even more of a Tear Jerker when
 * #49: The Diversion, where Tobias
 * #5, too.
 * When All You Have Is a Hammer: Given that it's literally their only weapon, the Animorphs' practice and use of the morphing technology far surpasses the Andalites' skill with it. This to the point of shocking Andalites like Ax and Aldrea, who watch the humans perform morphing acts that would count as legendary to their species yet let it pass without comment.
 * Where the Hell Is Springfield?: "Hard to explain elephants and rhinos attacking here in... well, never mind where here is."
 * Eventually averted in the last book, when the series is revealed to have taken place in California.
 * Why Did It Have to Be Snakes?: Tobias and going under water. Justified, though, given his species. Also, Ax, and other Andalites, are claustrophobic. Ketrans (the Ellimist's species before he ascended to near-godhood) can have panic attacks when indoors.
 * Why Won't You Die?
 * Wise Beyond Their Years: All the kids, to some extent, but Jake mostly.
 * With Great Power Comes Great Insanity: Certain forms, like ants, can rob one of sentience for a while. It's not always predictable, either.
 * A Wizard Did It: A lot of improbable things are chalked up to Ellimist and Crayak, such as the impossibly pacifistic Pemalites, the Contrived Coincidences in the Animorphs lineup (see the entry above on Can't Stay Normal), David finding the blue box and Tobias regaining his morphing ability.
 * Wonderful Life: Partially subverted. In Back to Before, the Drode asks Jake if he wants the war taken away. Jake, in a moment of weakness, accepts. What happens?
 * World in The Sky: The Ketrans' homeworld (Ket) in the Ellimist Chronicles.
 * The World Is Just Awesome: In #5, when the Animorphs are in space, they look back on Earth and comment that it's beautiful. In #7, the Ellimist shows them scenes of Earth, and says the same.
 * In #11 there's a moment where Ax sees all the glories of the rainforest in jaguar morph and says, "Your planet is amazing. Amazing."
 * Writtenbythe Winners: Interestingly, it's the humans that do this,
 * Write Who You Know: Applegate and Grant based most of the characters on people they knew. Applegate has said that the character Loren is based on herself. Grant is described as a lot like Marco but it's unknown if this was intentional (probably more of an author projection thing seeing as Marco's got an Expy in Grant's series).
 * Applegate also said Cassie was most like her, while Marco was most like Michael Grant.
 * Xanatos Speed Chess: The final battle eventually breaks down into this, as.
 * Ye Goode Olde Days: Averted in Elfangor's Secret.
 * Yank the Dog's Chain: Tobias' distant cousin has flown in from Africa and wants to take care of him. He can finally have a real family, stop eating roadkill and have a proper relationship with Rachel. He can have a normal life! This is awesome!
 * You Are Grounded: Stops being an issue after #25, when the Chee start impersonating the kids whenever they have to go away for long periods of time.
 * You Are Not Alone: A big thing, but most obvious in #31, when Jake's father is at risk of being infested. Jake's panicking and on the verge of having a mental breakdown, and is expecting a longwinded lecture from Marco about the importance of staying clearheaded and rational, instead of doing something stupid and reckless. But Marco just says, "You're not alone, man."
 * You Are Number Six: All Yeerk names and ranks have numbers attached.
 * You Cannot Grasp the True Form: The Ellimist.
 * You Can't Go Home Again: Ax tries to get home early on, but then decides it's better to help out on Earth and wait until the Andalites arrive.
 * You Did the Right Thing: Twice, after the war. Jake's most heinous act by far was After the battle, Cassie meets with Erek, who is shocked and disgusted that Jake would do such a thing. Defending Jake, Cassie heatedly replies that Jake "did what he had to do":

Cassie: No. Not guilty.

Erek: Then what?! He used me, blackmailed me, manipulated my programming to get me to crack the engine systems and take control of the ship.

Cassie: You drained the Dracon beams.

Erek: What did Jake expect me to do? I had given him control when he needed it. I wasn't going to enable him to kill.

Cassie: Jake had Rachel with Tom. Rachel and Tom are both... And the ship got away anyway. Thanks to you.

Erek: And I'm supposed to feel regret because Jake ordered his cousin to take out his brother and I wasn't going to let him kill everyone else on the Blade ship?! So, you too, huh Cassie?

Cassie: Jake did what he had to do.

Erek: Did he? Somebody flushed the onboard pool into space. Did he have to do that too? They were unhosted Yeerks. They were harmless!

Cassie: We needed a div -

Erek: A what? A what did you need? A diversion?! You're telling me you needed a diversion so Jake massacred seventeen thousand sentient creatures?! A diversion?!]]"


 * Similarly, during the war crimes trial of Visser One, one of the Visser's defense lawyers says that Jake himself should be under indictment as a war criminal for his actions. Jake, who has been clinically depressed for some time due to guilt, is cut deeply by this remark. Cassie, Marco and Ax later tell him that his actions were, if not wholly moral, were completely necessary; furthermore, Cassie makes the case that "you can't equate the victim and the perpetrator" when it comes to war crimes.
 * The book itself leaves things a bit more up to reader interpretation, and it's obvious that the characters saying so were significantly less sure of what they were saying than they would like to be.
 * You Have Failed Me: The Big Bad, Visser Three, was notorious for doing this on a regular basis. One Yeerk scientist actually preferred slow death by Kandrona starvation to what Visser Three would do to him.
 * You No Take Candle: The Hork-Bajir. Justified because the Arn genetically engineered them not to be very bright. A Hork-Bajir with genius-level intelligence is the result of a genetic mutation the Arn never quite managed to obliterate.
 * Even when they're being Controlled, a quirk of the brain causes them to trade languages around. (Gafrash!)
 * You Rebel Scum: "Yeerk filth!" "Andalite scum!"
 * Your Terrorists Are Our Freedom Fighters: A major theme of the book, with many an anvil dropped.
 * Your Worst Nightmare

Cinnamon BUN-ZUH!