These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Acceptable Hobby Targets: The Resistance features a family of Star Trek loving campers who are, to put it altogether too mildly, not portrayed in a very positive light. Star Trek fans reading the series later were not amused, though many of the Animorphs, particularly Marco and Tobias, are avowed fans of the franchise.
Cassie. Is she The Empath who genuinely does not like to emotionally hurt people and persuades others to not hurt others as well, but did what she had to in a war where the stakes were humanity and Earth? Or is she a sadistic, hypocritical and manipulative bitch that will leap at the chance to put someone to the psychological thumbscrews if the opportunity arises? Or is she simply a bit of a moron struggling through the war?
Tobias: Emo with wings, or The Lancer who, as he spends the first books unable to morph, is the only one able to objectively see the risks and benefits of each morph?
Marco, The Lancer, tactical and strategic genius, or just a fucking asshole who's only good for coming up with horrifyingly ruthless plans and complaining?
Jake, skilled leader, or just some insecure jock who made everything up as he went along and led five child solders to their inevitable War-is-Hell mental breakdown?
David, a lost and confused boy who's had his life completely destroyed and doesn't know if he can trust his "saviors", or a ruthless sociopath who has no qualms about murder and doesn't give a damn about the human race as long as he's safe?
And Taylor: Cold hearted torture technician or mentally damaged Broken Bird who can only express her bizarre love for Tobias by breaking the bird?
Anti-Climax Boss: Visser One/Three at the very end. Anyone expecting a climatic final battle will be severely disappointed when Esplin meekly surrenders to the kids and leaves his host with little fanfare. It's a bit of Fridge Brilliance, though, when one considers the Yeerk mentality mentioned way back in #06 The Capture.
This was actually specifically addressed by Applegate in her letter to the fans after the series ended, where she responded to criticisms about the finale ending the series on a down note. As she pointed out, such an anticlimactic ending—that is, the battle-hardened soldiers mourning their loved ones and confusedly trying to move on with their lives (and not always succeeding)—is a better illustration of how real wars end than a bombastic, fist-pumping final battle would have been.
Ass Pull: K. A. Applegate's a good enough writer to usually avoid these, but there's a really glaring one in the David Trilogy. The Threat ends with the cliffhanger that Tobias has been killed, showing David gloating over a very dead red-tailed hawk. Along comes The Solution and what happens? Tobias is very much alive, handwaved as just having 'gotten lost' looking for David, and that red-tailed hawk he killed? Just a random red-tailed hawk. Never mind the extreme unlikeliness of a red-tailed hawk following a golden eagle, a species known to be one of its few predators, into the enclosed area of someone's wrecked home, in the dead of night. (red-tails are very much diurnal animals, a fact which is pointed out in Tobias books before this more than once.)
In The Departure, we suddenly learn that metamorphosis resets the morphing clock, meaning that as soon as Cassie became a butterfly, she was no longer a nothlit. This was never mentioned before or after that book.
Bizarro Episode: Cassie has a book that's one, The Hidden. A random buffalo somehow acquires morphing powers as the Yeerks cause trouble with Helmacron technology. It's as bad as it sounds.
Megamorphs 2: In The Time of The Dinosaurs: A nuclear sub explodes, tearing a hole in space-time that sends all the Animorphs to the time of the dinosaurs. They meet the Nesk and the Mercora species, getting caught in the war between the two. For reasons never explained, morphing won't heal Tobias's broken wing in this adventure.note Applegate later admitted that she wrote "Tobias breaks his wing" in her summary to her ghostwriter after forgetting that morphing can heal injuries. The ghostwriter thus wrote a scene of Tobias trying to heal it but finding it can't. The K-T extinction comet arrives and kills all the dinos and aliens, as well as rocketing the Animorphs back to their own time. After this adventure, the Animorphs find they can not morph into their acquired dinosaur forms.
The Forgotten also counts, for similar reasons. In fact, any book written with the Sario Rip effect is an instant candidate for a Bizarro Episode.
For a non-Saario Rip example, there's The Prophecy. A sequel to The Hork-Bajir Chronicles where a recording of Aldrea's personality is put into Cassie. Except the process comes off as pure voodoo that sticks out strongly in this mostly hard sci-fi series, and Aldrea is inexplicably considered to have chosen to become a Hork-Bajir nothlit rather than being knocked out. Plus, there's a glaring editing mistake that makes the Animorphs look like idiots when they're all shocked and appalled that Aldrea doesn't known where the book's MacGuffin is, after she already told them.
Broken Base: Some fans liked the secret-guerilla-war aspect of the series, and thought the final story arc ruined the series. Others, conversely, see the final arc as ten shades of epic, and see it as the best-written and greatest part of the series.
Similarly, some fans liked the, uh, open-ended conclusion, as it brought the series full circle. Some thought it was just an easy (and lazy) way for Applegate to get out of writing a real ending.
Esplin 9466 (the greater), better known to the cast as Visser Three. The only Andalite-Controller in existence, Visser Three is the sole Yeerk with the power to morph. In his first appearance in the series, he shifts into a horrific monster and eats Prince Elfangor alive, firmly establishing his characterisation for the rest of the series. A low-functioning sociopath with a Hair-Trigger Temper, Visser Three takes every opportunity he can to kill people, personally decapitating his subordinates and their hosts left, right, and centre. He repeatedly eats those he dislikes, and outrages other Yeerks when he morphs a Yeerkbane, one of their few natural predators, and uses it to devour subordinates who have failed him. As the commander of the invasion of Earth, Visser Three cares nothing for casualties, and is willing to write off thousands of his own Yeerks, rather then negotiate. He is the worst boss in the series, and no matter how awful things got, always gave the Animorphs the most nightmares.
Crayak, is a Sufficiently Advanced Alien who acts as the series' satan equivalent. A nearly omnipotent Social Darwinist, Crayak seeks to create a universe ruled by one species and one species alone. To that end, Crayak engineered the Howlers, a race of psychopathic child soldiers who think that killing is a game, and used them to gruesomely exterminate countless species, including the pacifistic Pemalites and Graffen's Children. In order to ensure that the Howler's Hive Mind is never contaminated by memories of defeat, Crayak obliterates any Howler's who fail him; he also destroys any Howlers who realise that their victims are people too. Not content with having created one of the most feared races in the galaxy, Crayak also lends his godlike might to other vicious species, secretly backing the Yeerks and other would-be galactic conquerors; he plans, for example, to have the Yeerks enslave humanity, only to then be wiped out by the Howlers. In a series filled with shades of grey, Crayak was as close to pure, unadulterated evil, as one was likely to get.
While she might not have operated on the same scale as Visser Three or Crayak, there were few antagonists in the series who could match Subvisser Fifty-one—better known by her host's name of "Taylor"—when it came to sheer visceral cruelty. A case study in why one does not allow an already Axe CrazyYeerk to infest a mentally ill girl, "Taylor" combines her host's anger with her own Yeerk ruthlessness to deadly effect, acting as Visser Three's Torture Technician. Capturing Tobias she subjects him to brutal torture, using a device that tampers with the pain/pleasure centres of the brain, forcing him to relive the worst moments of his life, or inserting agony into even the fondest memories. When his friends try to rescue him, she runs off with him and starts torturing him physically even as she makes her escape, stopping only when Rachel finally frees him. Returning months later, the demoted subvisser reveals she has severed her mental link with her host, regaining much of her sanity, but none of her morality. Manipulating the Animorphs into helping her with a plot to kill Visser Three, "Taylor" relentlessly taunts Tobias about her treatment of him, trying to provoke him into a fight so that she'll have an excuse to hurt him some more. She then reveals that her actual plan is to blow a gas main near the Yeerk Pool, killing thousands of her fellow Yeerks; she will then pin the blame on the Yeerk Peace Faction. An insecure bully possessed of a raging inferiority complex, "Taylor" is the postergirl for everything wrong with the Yeerk military, and shows just how banal even the sickest individual can be.
Creator's Pet: Arguably Cassie. She's the stated favorite of writer K.A, she is the only character in-series to win the Superpower Lottery (being both an estreen and a temporal anomaly) and she is usually praised and defended by the narrative even when it's completely unwarranted - take for example Megamorphs #02, when Marco privately compliments Cassie for going on a whiny rant about killing a Triceratops, or #53 The Answer, when Tobias harshly criticizes Jake for excluding Cassie from the war council despite the fact that he had extremely good reason to (that reason being that she betrayed the whole team by allowing the blue box to be seized by the Yeerks, and all for a 'gut feeling' that she's lucky to see pan out). She criticizes the others from start to finish, puts the whole team at risk on multiple occasions, and is the only character to never learn or grow in any way. This even extends to the epilogue, where she is the only Animorph spared by the Bolivian Army Ending.
Creepy Awesome: Despite appearing in only one book, Joe Bob Fenestre stands out as one of the series' most intriguing antagonists. Possibly because he's the Animorphs equivalent of Hannibal Lecter.
Ensemble Darkhorse: Tobias and Ax both qualify. They were given only one book per ten-book cycle because Scholastic didn't think they'd be as popular as the four main kids. Boy were they wrong about that...
Escapist Character: Tobias counts as this for a lot of first-time readers. What kid doesn't want to just fly away from their problems?
Evil Is Sexy: Subverted. Taylor is described as very attractive, but is so artificial and emotionally screwed up that no one cares. Pointed out by Tobias when he morphs Taylor and recieves far more positive male attention than the real thing:
"We were mirror images, literal carbon copies. But I was alive. Taylor wasn't. Not really. I had a sense of humour. Taylor had a coldness that enclosed her like a shield. The kid could see this. Anybody could."
Foe Yay: Largely averted between Taylor and Tobias. It is possible to read her obsession with capturing and breaking Tobias (and some of the lines she says to him) as rather Foe Yay-y, but it requires you to ignore her personality. She's described as so cold, nasty, and downright insane that most of it comes off exactly the way it's supposed to: as the behaviour of an insecure, sadistic bullying bitch who doesn't like letting her victims get away. Yandere she ain't.
Arguably, David and Rachel — he also gets in a We Can Rule Together line in book 22 (his specific words are "we could hook up," though that might just be '90s slang), and there are hints that the team (well, mostly Cassie) picked up on the dynamic between them and used it to trap him.
Fridge Horror: David's fate - rats only have a lifespan of two to three years. So instead of a death sentence, the Animorphs just gave him a slightly prolonged death sentence.
Game Breaker: Cassie, in-universe. Her natural ability as a 'temporal anomaly' allows her to see through the reality warping powers of beings like the Drode, and her presence in any timeline that's not the 'real' one will ensure the fake timeline breaks down. Lampshaded by the Drode himself, who angrily accuses the Ellimist of 'stacking the deck' by including her on the team.
In the alternate future Jake visits in #41, the only part of the New York skyline still recognizable is the World Trade Center.
In book #37, Rachel deliberately crashes an airplane into a skyscraper.
Also, in book #46, there is discussion of how America is complacent because they have no real enemies. And then Ax threatens to fly a plane over the middle of a town and detonate a nuclear device.
In book #54, which was published in May 2001 but set in 2002 or thereabouts, Jake mentions that since the existence of aliens was revealed to the general public there's been a rise in terrorism, particularly religiously motivated terrorism.
In Megamorphs #2, the Animorphs help rescue a nuclear submarine that has gone down. After they finish, Ax asks what the submarine is for, since he figures it’s too large to be an exploration vessel. Jake explains that it’s part of the navy, which leads to this conversation:
<Well . . . okay, we don’t exactly have one right now,> [Jake] said, feeling fairly idiotic. <But we used to. And we may get one again.>
<We’re shopping all the sales,> Marco said brightly. <Enemies “R” Us, Enemy Mart, J.C. Enemy. Don’t worry, we’ll find one.>
The final arc, which featured a War Is HellAesop was gut-wrenching, incredibly sad... and came no more than four months before the U.S. entered an actual war.
Hilarious in Hindsight: More than a decade after the series ended, Applegate wrote another book featuring talking animals, specifically a gorilla and an elephant. Granted, they had no similarities to Marco and Rachel whatsoever, and since it was based of real events, they had to be those animals, but it's still pretty funny.
The Conspiracy has been criticized for being an idiot plot, both on the part of the yeerks and the Animorphs.
The Answer has had similar criticisms.
The recurring plot with the Yeerk Peace Movement can also be taken as an idiot plot, in that the Yeerks could always infest animals that weren't sentient, as proved in The Unknown.
Also, The Hork-Bajir chronicles has a small element of this, because the Arn never think to create quickly-reproducing bodies for the Yeerks to infest.
It Gets Better: The beginning of each book is loaded with the same exposition about the Yeerks and "I can't tell you my last name" and "We can't stay in a morph for more than 2 hours" and "You see, every three days they have to..." and so on.
David - lost his entire life through no fault of his own, was kidnapped by kids he didn't know and forcibly recruited into a war he wanted no part of and faced the threat of death from both sides of the conflict. His final fate just hammers the nail in.
Taylor - lost her arm, leg, and face in a fire. Became a human-Controller in exchange for getting them back. Got infested by a psychotic Yeerk, whose fusion with her own unbalanced mind drove them both over the edge. She'd be pitiable if she weren't so evil (this applies to Taylor the Girl, and not her Yeerk Subvisser Fifty-one).
Mary Sue: Deconstructed with Estrid. Gets hit on by a main cast member, genius, expert tail fighter, estreen, got into a university despite sexist Andalite beliefs... And all it did was get her recruited into a secret project to eliminate the Yeerks via biological warfare, a mission it's implied that they would have executed her for by the end of it to keep it covered up and avoid controversy.
Magnificent Bastard: Visser Three and Visser One approach this in their respective backstories, before the Villain Decay(and in Visser Three's case, insanity) set in. David and Tom both fancy themselves to be this, but are usually seen as just Smug Snakes. The one who probably comes the closest to this trope is, of all people Jake who really cracks out the gambits before diving into What the Hell, Hero? territory.
Drode: Oh, I see it now, I see it now. Subtle as always, Ellimist. Your meddling came before, didn't it? How could we not have seen it? Elfangor's brother? His time-shifted son? This anomalous girl here? And the son of Visser One's host body? A group of six supposedly random humans that contains those four! You stacked the deck!
There's a rather infamous spoof cover of Cassie morphing into a watermelon Yeah.
And then there are those with celebrities with animal names morphing into their respective animals, e.g. Pitbull, Seal, Snoop Dogg (after he renamed himself Snoop Lion)... and even Sarah Jessica Parker morphing into a horse (because according to Memetic Mutation she looks like one).
Moral Event Horizon: David's murder/replacement of Jake and Rachel's cousin Saddler is played this way. Previously given some sympathy due to his having lost his parents and been forcibly recruited by the Animorphs into a war he doesn't want to fight, David's attacks on Tobias and Jake were the start of a slide down the slope to straight up villainy, but were not unforgiveable. David's decision to unplug Saddler, stash the body, and replace him, is the point at which the characteres and the narrative stop treating him with any sympathy, and the point at which the audience realises that there is going to be no reconciliation.
Some members of the fanbase—and Jake himself for that matter—view his execution of 17000 defenceless Yeerks as one of these. While Jake clearly feels bad about it, it's an action from which there is indeed, no going back.
Narm: Rachel threatening David with a plastic fork in the ear. It's both intensely disturbing and somehow hilarious in its simple and straightforward language.
"He stepped back, drew back his fist, and swung on me. I dodged the blow. I grabbed his head with one arm and jammed the fork against his ear. I fought a nauseating urge to twist the fork, to make him scream in pain."
Only The Creator Does It Right: Frequently invoked by the fans in response to the ghostwritten books. Scholastic themselves invoked it once, when K.A. had to do a last-minute rewrite of #28: The Experiment. Amusingly, the much-maligned #32 The Separation is frequently cited as an example, when in fact that book was written by K.A. herself.
Paranoia Fuel: Thanks to their fantastic capacity for imitating their hosts, Yeerks can be anywhere, even inside the people you know intimately. Yes, you could be talking to an alien parasite who's putting on an elaborate act and doesn't mean a word he/she says while your genuine best friend/close sibling/beloved parent/ significant other is watching you be fooled, and is mentally sobbing because no one realizes they're a prisoner inside their own head, and you'd have no way of knowing. At all. The yeerks make a few rare mistakes, due to having their own agendas and personalities, but aside from a couple isolated incidents the yeerks are absolutely undectectable. Combined with the books' Literary Agent Hypothesis setup, this makes for some very creepy Mind Screw.
Also because ot the Literary Agent Hypothesis, you realize that the insect you just killed could have been one of the Animorphs.
Even though the Chee are good guys, the concept of people around you being Nigh Invulnerable extraterrestrial robots using holograms to make themselves look human is rather unsettling.
Scrappy Mechanic: The Sario Rip effect. It's a thinly-veiled way to send the kids on fantastical journeys to places like the Amazon or the Cretaceous, and it comes with a built-in reset effect that makes anything that happens during it irrelevant. The kids get all kinds of cool morphs they don't get to keep because of it, and the books where it is featured are usually a lot less fun than they were meant to be.
They Wasted A Perfectly Good Character: An unfortunately inevitable outcome of combining ghostwriters with a series featurings Loads and Loads of Characters. Some of the best villains the series produced, like Joe Bob Fenestre in The Warning and Arbat-Elivat-Estoni from The Arrival, were one-shot characters that were never seen again. Other characters, like Aftran 942 and David, returned irregularly but are lamented among fandom for never being utilized in the way they deserved to be.
Trapped by Mountain Lions: Rachel, of all people, is subjected to this in the first Megamorphs book, The Andalite's Gift. The first half of the book has her contracting an unfortunate case of Easy Amnesia and wandering around the woods while her friends are fighting for their lives.
Taking the series as a whole into account, entire books can count as this. The Mutation, The Hidden and The Journey are great examples of entire books featuring the Animorphs getting caught up in bizarre and irrelevant sideplots that have no consequence to the main conflict of the Yeerk invasion.
Also, David, who never stops whining about how unfair it is that he's "lost everything" even as he tries to murder the kids.
What Do You Mean, It's for Kids?: In VISSER, there are several implicit references to drugs. Jenny Lines is heavily implied to be a drug addict when Edriss said in the narration, "The only thing she really cared about was a certain human substance." They couldn't actually say what the substance was…
This also apples to Hildy in the same book; he was heavily implied to be an alcoholic. To get him to talk, Visser Three said he'd give him a "bottle", but Applegate couldn't exactly say what was in the bottle.
In recent years, the books have had a relatively large following with adults who read the series as kids. Some adults are just now discovering it, without knowing that it was intended for children. It's not hard to see why - it's incredibly dark and violent, and there are some concepts (such as drug abuse) subtly (or not-so-subtly) presented in the text that a kid simply wouldn't get.
Tobias. He starts the series out as a skinny, blond-haired loser Jake saves from bullies... and Jake is the closest thing he has to a friend, despite the fact Jake thinks he's weird. His parents are dead, his only two relatives fight over which one of them HAS to have him. He then gets trapped as a hawk by the end of the first book. He then goes on to have an epic identity crisis, start a semi-Interspecies Romance with a girl who really wants him to drop the "interspecies" bit, realize that the alien who died saving them is his father, get captured and tortured, realize that his mother isn't dead — she's amnesiac and crippled, and watch Jake send the love of his life to certain death. About the only good things that happen to him are Rachel, his girlfriend, and Ax, his best friend and uncle. They both die. For a series as dark as this one, Tobias stands out for his Woobieness.
The worst part is that he honestly feels his new situation is an improvement. Stuck fighting an alien invasion involving thousands of conspirators with only four human kids while trapped in the body of a hawk and fighting the instincts of the hawk to retain his own humanity is a step UP for him.
Really, every character falls into some category on the Woobie spectrum. Even David has his moments. About the only one who can't be considered Woobie-ish to some extent or another is Visser Three himself.
The Yeerks are the misunderstood variety for the most part. They are blind, sentient slugs who only take hosts to compensate for their biology. Only those in power and those seeking power can be said to be really evil, as most of the footsoldiers are either swept up in the propaganda or afraid to challenge their superiors.
The Taxxons suffer from terrible Horror Hunger. They're a race of terrified over eaters, cannibalising one another out of a terror of starvation.
The Hork-Bajir were race of dumb, friendly bark eaters who were nearly wiped out in an attempt to deprive the Yeerks of hosts.