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 — and Applegate herself — are avowed fans of the franchise.
When the tiny Helmacron spaceship lands in a Goodwill store, Jake pretends to have accidentally donated his toy spaceship and asks the worker if he can get it back. The worker suspiciously asks him what kind of spaceship, and rattles off a list of alien spacecraft from Star Wars, Star Trek, and Babylon 5, leading Jake to mutter about of all the workers in all the Goodwills, they got the one who happened to be a sci-fi geek. This is less a dig at being a sci-fi fan (Cassie and Rachel also speculate on it, and deliberately go to Jake because he would be able to choose the franchise that the Helmacron ship would most likely pass as a toy from), and more a dig at the inconvenience of their bad luck.
When Sixth Ranger Traitor David is introduced, one of the early hints that he isn't to be trusted is the fact that he likes heavy metal bands like Megadeth and horror comics like Spawn, compared to the tamer works that the main characters prefer.
Surprisingly averted when the world's politicians have their summit meeting in the David trilogy. Played straight with Nazis, who are semi-regularly mentioned by the kids as a shorthand for evil. Though the summit meeting scene manages to slip in a comical shot at a certain world leader with a comical drinking problem. Probably Boris Yeltsin, for those of you who aren't 90's literate.
At one point in the epilogue, several Right-Wing Militia Fanatic groups spring up in response to the discovery of aliens. Not much depth is given to them.
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 an asshole who's only good for coming up with horrifyingly ruthless plans and complaining?
Jake, skilled leader, hardened manipulator who use his friends as tools, 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?
Erek: admirable pacifist or manipulative hypocrite?
Visser Three (aka Esplin 9466): Andalite-hater who wants them dead both because they're enemies of the Yeerk empire and because he's jealous of their natural freedom, or secretly an Andalite-lover who sees Elfangor as the one he admires most, plus harbors a twisted crush on Aldrea? Or possibly all of the above? Is he an incompetent villain that was only promoted because he got lucky and infested Alloran, or do his actions in the Chronicles indicate that he was once a Magnificent Bastard with just as much ability to plan ahead as Visser One only for the power he gained when he infested Alloran to drive him to madness (or at least complacency)?
How even was the war between the Yeerks and the Andalites? While most sources within the books claim them to be deadlocked and Earth as the keystone that will win the war, at least one article has claimed that there's a lot of clues that the Andalites were beating the Yeerks handily and Earth is more like their only hope for victory—if true, it definitely doesn't cast the Andalites in a positive light.
Alternate Aesop Interpretation: Megamorphs #4 seems like it's saying that if the Animorphs just come forward and scream the Yeerks are here, it'd be much more effective then secretly working to dismantle the invasion. Seems similar to criticism leveled against Pope Pius XII for secretly doing minor help for Jews in World War II instead of coming out loudly decrying Hitler and Mussolini.
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. Admittedly this one is somewhat justified, as there wasn't really a reason for it to come up prior to this book (any attempt at introducing it earlier would have come across as a painfully obvious Chekhov's Gun), but it's still pretty jarring to have the climax of the book rely on a rule the audience was never aware of.
Cassie is practically the walking personification of this. Half of the fandom has practically taken up "Cassie is a moron" as a catchphrase thanks to her numerous instances of poor judgment, while the other half sees her as the most human and relatable of the Animorphs." Much like anything involving David, this can lead to major backlash, so we'll just leave it at that.
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 open-ended conclusion, as it brought the series full circle and tied in well to the War Is Hell message of the series. Others thought it was just an easy (and lazy) way for Applegate to get out of writing a more conclusive ending.
The Experiment gets a lot of flak for being a poorly-plotted anti-meat screed (which even Applegate herself thought was obnoxious), but it also has its fans for the genuinely funny comedy throughout.
The second Megamorphs book. Fans either love it for the fanservicey premise (The Animorphs go back in time to fight dinosaurs!) and its fun action-movie pacing, or they absolutely hate it for its questionable logic, inconsistencies with the rest of the series, and a particularly character-derailing ending. It's almost like the Planet X of Animorphs books.
Complete Monster: In a series full of shades of grey and with a theme of War Is Hell, a select few stand out as truly monstrous and evil individuals.
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 morphs 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, by 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 than 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 an alien and member of The Highest Powers who acts as the series' God of Evil. 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 Howlers' Hive Mind is never contaminated by memories of defeat, Crayak obliterates any Howlers 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.
Subvisser Fifty-one, also known by her host's name, "Taylor", is a cruel Yeerk. Infesting the mentally ill girl, Taylor becomes an angry monster who serves as Visser Three's Torture Technician. Using a device that tampers with the pain and pleasure centers of the brain, Taylor captures Tobias and makes him relive the worst moments of his life and inserts agony to the recollections of his best memories. Returning months later after Tobias is rescued, Taylor reveals she severed her mental link with her host, regaining her sanity but not an ounce of morality. Taylor manipulates the Animorphs into helping her kill Visser Three, taunting Tobias about the suffering she put him through, hoping to provoking him into attacking her so she has an excuse to hurt him more. Revealing that her actual plan is to kill thousands of her fellow Yeerks, Taylor intends to pin the blame of her attack on the Yeerk Peace Faction.
Continuity Lockout: The first graphic novel manages to never establish that Jake and Rachel are cousins, leading to some jokes by fans about how the new readers it's trying to reach might start shipping them only to later find out they're related.
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.
Critical Research Failure: Some of the later ghostwritten books where the Animorphs travel to places like Australia and faux-Atlantis have these. At this late date it's hard to say whether or not they're just honest mistakes.
Darkness-Induced Audience Apathy: Animorphs was never a particularly lighthearted series but by the end it's comparable to Game of Thrones. The main characters are traumatized anti-heroes at best and psychopaths at worst, (see Alternative Character Interpretation) both sides of the military in the Yeerk vs. Andalite war have been shown to have committed atrocities to the point where it's hard to say that anyone is morally superior, most of the humans are horribly outmatched and have virtually no say in their fate, when the Animorphs finally call the Andalite homeworld the aliens' response is to "Quarantine" planet Earth, thereby mark it for destruction, and to top it off two god-like characters, one named Crayak and the other named the Ellimist, are locked in a "game" that might result in the universe being destroyed.
Do Not Do This Cool Thing: An in-universe example: many of the first twenty books in the series open with the Animorphs engaging in comedic shenanigans using their powers while in the process breaking a wide range of laws from breaking-and-entering to theft to assault and possible murder towards people they judge as deserving it. Skip ahead to the David trilogy and the team contracts a shared case of Moral Myopia, with Jake threatening new Animorph David for the relatively tame sin of breaking into a hotel room.
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?
Ethnic Scrappy: Some of the one-off side characters like Derek the Inuit from #25 and Yami the Aboriginial boy from #44 dance on the edge of this due to having little characterization beyond their respective ethnic stereotypes. At least Derek gets to be a Trekkie and an Unfazed Everyman.
Subverted with Taylor, who 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 receives 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."
A lot of fans simply gloss over some of the more awful ghostwritten books.
The ending of the series (spread across several books) is this for many people, partly for the lack of a proper conclusion (featuring an infamous Bolivian Army Ending), partly for being much Darker and Edgier than the rest of the already fairly dark series, partly for making several protagonists extremely hard to root for, and partly for being full of Nightmare Fuel.
The Transformers Animorphs tie-in action figures are disregarded by both Animorphs and TF fandoms because, like the TV series, they sucked, though the concept sounded pretty good on paper. It was the execution, specifically the Kibbles and Bits syndrome that hit the line hard (due to the fact that toys can't mimic the Animorph's transformation fluidly); that was the downfall. (The Mutant Beast Wars animal-to-animal toys that came out afterward were intended for this line; you can tell because one head is clearly an Andalite head.) The later Star Wars and Marvel TF toys have been better received.
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. The attraction seems to come more from Tobias's end, with the way he compares and contrasts her with Rachel (especially Taylor's physical beauty, which he mentions several times), the thrill he gets from morphing her body, and how he relates her to himself.
Though if you look hard enough...in Taylor's second book, there's a brief moment where she freezes up mid-conversation and then whispers "Don't trust her"; Taylor the Yeerk was indeed deceiving the Animorphs throughout that book. This warning can be construed as Taylor the human managing to briefly reassert control; compare Chapman and his wife fighting their Yeerks in book #2 to protect their daughter and you have to wonder...
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 because he'd "get so much sick pleasure out of forcing her to obey him." Though in Rachel's case, it wasn't even remotely reciprocated.
David definitely has a weird thing about Rachel that is at least partially sexual—while all the kids (except Ax) call her pretty, he really spends a lot of time talking about her looks, and, of course, <Enjoy your shower.>
If you squint really hard, you can see that Esplin might have a Villainous Crush on Aldrea.
There was one with Goosebumps, as both were in the height of their popularity at the time the books were being published.
There's also one with Gone, since both involve kids getting superpowers by an alien force, and it was written by Applegate's husband and co-writer, Michael Grant.
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 book #12, when Cassie morphed Rachel, she complained about the morph being hard to control because Rachel's instincts kept trying to make her do stupid things. As the series progressed, readers started to see some of what those instincts were - extreme violence, recklessness, and so on. It gets even worse once you reach book #54 - Cassie's best friend is gone, and the closest she'll ever get to having her back is morphing her.
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.
In megamorphs #3, the story begins with an alternate timeline where everyone has slaves. Cassie's slave is called "September Twelve".
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 its too large to be an exploration vessel. Jake explains that its part of the navy, which leads to this conversation:
<Well . . . okay, we dont exactly have one right now,> [Jake] said, feeling fairly idiotic. <But we used to. And we may get one again.>
<Were shopping all the sales,> Marco said brightly. <Enemies R Us, Enemy Mart, J.C. Enemy. Dont worry, well 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.
In book #22, Rachel mentions that the Yeerks could get human-Controllers to machine-gun them inside a Taco Bell and it would barely register as news to humans. For context, this book came out before Columbine, let alone before mass shootings became a regular occurrence.
In book #2, Rachel thinks she's alone on the Blade Ship only to find Jake is in flea morph on her back because he wasn't going to let her go alone. Come book #54, Rachel is on the Blade Ship alone...except this time, no one is there with her.
An early example of this came in the ninth book, The Secret. The gang fools Visser Three into taking a bath in grape juice to get rid of the smell of skunk. This becomes even more hilarious when it is later revealed that Andalite females are purple.
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.
One Running Gag had Jake and Marco arguing whether Batman or Spider-Man would win in a fight. Death Battle has since done a segment featuring the two ( Spider-Man wins with a lack of prep-time on Batman's part), and later still, Spider-Man ends up fighting "Batman" in Spider-Man: Homecoming.
Applegate apparently never watched the TV series past the second episode, yet later wrote Megamorphs #4, which has basically the same plot as one of the original episodes, except backwards: in the episode, Tobias still becomes an Animorph while the others are infested, but in the book, he gets infested while they fight the Yeerks.
The whole concept of the series—teenagers who acquire animal DNA in order to "morph"—would later come to describe another series a little too well.
The reason behind the Howlers wanting to kill everybody, the fact that they're basically just children who think real life is a game and don't realize they're acutally killing people, is extremely similar to Harley Quinn's "Harleyvision".
The revelation that Hork-Bajir are actually herbivorous and use their massive blades to shear off tree bark became this for paleontology nerds when it was discovered that the infamous Therizinosaurus, notable for its gigantic bladed claws, was also a plant-eater. (Hell, with its long neck and birdlike head, it even looks a lot like a giant tubby Hork-Bajir.)
The Conspiracy and The Answer have both been criticized for this trope, both on the part of the Yeerks and the Animorphs.
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.
More generally, as far as we ever find out there is absolutely no limit on how many morphs can be acquired, which makes it a bit odd that the kids all insist on having their own specialized morph for various situations rather than everyone just acquiring as many animals as they can.
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).
Alloran released a quantum virus on the Hork-Bajir homeworld in an attempt to prevent the Yeerks from using their bodies. His actions resulted in thousands of innocents dying painfully. At the same time, it's kind of hard to not feel bad for him. He spent years imprisoned in his own body, begging Ax to kill him when he was free momentarily. He had to watch, powerless, as his body was used to murder countless people and even eat them alive. He had a wife that he named his ship after and two children that he went decades without seeing. After he was freed in The Beginning, he was shouting in excitement because he could move out of his own volition. Given Visser Three's penchant for torturing those under his control, one can only imagine what additional torment Alloran was forced to endure as a captive mind in the brain controlled by the Visser. Alloran's exuberance when the Visser is defeated is palpable, as he swings his tail blade for the first time in decades on his own accord.
Alloran: <Do you know who did that? Do you know who moved my tail? I did. I did. I did it.>
There's a rather infamous spoof cover of Cassie morphing into a watermelon.
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).
Thanks to some offhand comments from Visser Three in the first two books about Jake's lion morph and Rachel's cat morph, "Visser Three loves kittens!" has turned into one of the more enduring inside jokes of the fandom.
"Dapsen", implied to be a vulgar word in the Yeerk's language, frequently shows up in humorous fanfics from Yeerk characters' points of view.
David murdering 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 attempts to kill on Tobias and Jake were the start of a slide down the slope to straight up villainy. David's decision to unplug Saddler, stash the body, and replace him, is the point at which the characters and the narrative stop treating him with any sympathy, and the point at which the audience realizes that there is going to be no reconciliation.
Some members of the fanbase—and Jake himself for that matter—view his execution of 17,000 defenseless Yeerks as one of these. While Jake clearly feels bad about it, it's an action from which there is indeed no going back.
It's hard to say where exactly Rachel crosses it, due to #32 being a case of a Superpowered Evil Side run amok and #37 having some inconsistent writing, but by the time of #52 she's firmly in Sociopathic Soldier territory, chasing down a deserting Yeerk MookFor the Evulz and then nearly committing vehicular homicide on the mild-mannered Captain Olston. It's implied that even Rachel herself realizes that she's too far gone when she agrees to go on that last mission for Jake.
Narm: Rachel threatening David with a plastic fork in the ear. It's both intenselydisturbing 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."
One-Scene Wonder: The ant that gained the power to morph from the blue book and has a run in with Cassie.
Pair the Spares: Possibly. One episode of the tv adaptation ends with all six protagonists slow-dancing to a romantic song: Cassie and Jake, Rachel and Tobias, and Marco and Ax. In the US, this was the last episode aired, and it's pretty easy to interpret it as a Last Minute Hookup.
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 of 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.note Pretty much the only difference between the Chee and Terminators is that the Chee are Actual Pacifists. Now imagine if that weren't the case...
Scrappy Mechanic: The Sario Rip effect is a rare non-video game example. 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.
Slow-Paced Beginning: 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. Some fans make it a habit to just skip the first few pages of each one.
Strangled by the Red String: Official Couple Rachel/Tobias is a curious case. Back when the series was originally being printed it was the Animorphs pairing of choice, to the point where the TV show reinvented Tobias from The Chew Toy into the resident badass to better mesh him up with her. But as the fandom's matured, a lot of the more uncomfortable aspects of their relationship have been acknowledged, such as Tobias' attraction to other females — namely the female red-tailed hawk — and especially his obsession with Taylor. Then on Rachel's side, she doesn't seem interested in Tobias himself so much as she is the idea of Tobias, to the point where when she was split in two during The Separation her "good" side had no interest in Tobias at all, and her bad side — while respecting him as a fellow warrior — was still perfectly willing to kill him if she needed to. Also, although real Rachel has said "I love you" to Tobias, he's never said it back. Not too mention, in alternate timelines, they both dated other people (Rachel was dating Marco in one timeline, Tobias was dating Melissa in another).
An unfortunately inevitable outcome of combining ghostwriters with a series featuring 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 the fandom for never being utilized in the way they deserved to be.
Loren has an incredibly emotional reunion with her son Tobias and gets morphing powers herself during her rescue, and then mostly just sits around for the remaining few books.
Toby Hamee is the Hork-Bajir seer. She's the great granddaughter of Dak and Aldrea, and personality-wise is far closer to Aldrea because she is much more ruthless than Dak ever became. She was an incredibly effective general, and had more long term plans than any other character. And she showed up about six times throughout the series.
The Auxiliary Animorphs, the handicapped kids who are also given the morphing power are mostly used as Red Shirt's in the last couple books despite some good potential.
Rachel's little sister Jordan feels like she could have been better involved in the plot, especially given that she does seem to sense something's up at one point and asks Rachel to trust her.
Chapman's daughter Melissa starts as Rachel's good friend who then becomes distant due to her confusion at why her father is suddenly so distant from her in turn, but her importance quickly fades, and she even suffers the indignity of her final appearance being in an alternate timeline that's wiped from existence at the start of Megamorphs #3.
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.
Wangst: David, who never stops whining about how unfair it is that he's "lost everything" even as he tries to murder the 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. This has spawned the popular fandom joke that K.A. told Scholastic it was a bottle of milk.
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. It doesn't help that the TV series toned down the violence.
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. (Although Jake at least seems fond of him, despite finding him strange.) 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 ones in the Yeerk invasion force have it particularly bad, as they've been removed from the Hive Mind that usually regulates their hunger.
The Hork-Bajir were race of dumb, friendly bark eaters who were nearly wiped out in an attempt to deprive the Yeerks of hosts. The kicker is that it didn't even work. Those few Hork Bajir who weren't killed were successfully infested with Yeerks.
That one time Marco had a dream about being chased by a stop motion T-Rex (stock footage from another movie). Presumably it was supposed to be a Hork-Bajir, because it makes the exact same noises.
Technically the time Tobias was shot dead and randomly recovered, because it was never mentioned again and had no impact on anything.
For lord knows what reason, the first few episodes of season 2 were utterly meaningless to anything that would happen in the episodes following. This is especially glaring compared to the 3-parter that made up the second half of the season (Season 2 was 6 episodes long)
Even for this show, the oatmeal weaponization episode was pretty ridiculous. To be fair, it was actually adapted from the novel's own Bizarro Episode.
Episode 4. Nothing actually happens and Tobias's disappearance is almost never mentioned.
Not my Problem. The Ellimist appears to Jake. Jake randomly decides to become infested. Tobias must save everyone. And then it was All a Dream. This is actually one of the better episodes all things considered.
The most obvious example is Episode 11. Jake has been infected, and somehow Ax and Tobias are the only characters that realize that he is. There are several weird things about this.
Ax realizes Jake is infected because of a gesture Jake makes with his ear. The thing is, Marco recognized Tom as a Yeerk the same way back in episode 2, so Ax being the only one to notice it is... odd.
Jake-Yeerk realizes he can just wait for someone to let their guard down, then morph and run away. He decides to morph... Jake's dog to do it. Something anyone on surveillance duty would find suspicious.
On a related note, Rachel and company are lucky he doesn't decide to morph Tiger or something, or they'd all be dead.
PLUS Jake's Yeerk dies of starvation moments after he leaves, meaning that even if he wasn't caught immediately, he'd he dead.
And of course there's the little detail that the only character to figure out something's up, was the one who wasn't there when Jake dipped his head into the Yeerk pool!That's an interesting coincidence.
Tobias doesn't become a hawk until episode 3. This could open up the chance to explore who he was before the transformation. But instead he gets an odd subplot where he gets paranoid about the morphing and runs off for a while, leading the others to worry that he sold them out until he redeems himself.
...Which leads to another wasted plot. Tobias is the outsider of the group, so a few trust issues would be interesting to work with. Instead, the show focuses on whether he actually is trustworthy, which most people'd be able to guess.
...Leading into what happens next. When Tobias goes missing, they wait a few episodes to reveal what happened to him. Perhaps a little more reaction from the main cast would have been nice?
Rachel Morphs a Yeerk to help Tobias infiltrate the Yeerk pool (something the novel characters are too disgusted to do). His infestation leads the others to believe he's been captured. The definitely could have been utilized for more than a brief confrontation scene.
Hell, infiltrating the Yeerks is an awesome idea, and no-one ever brings it up again.
The resistance. To be fair to this one, this is when the show was abruptly cancelled.
Infested Jake tries to sway Tobias into letting him go by saying the Yeerks have the Tech-know how to change him back to human. He backs this up by saying that Jake really thinks of him as the team-pet. To the show's credit Tobias (as a hawk, no less) actually manages to look rather torn about it, quickly leaving the second Rachel comes to take over his shift.
Rachel gains amnesia. Unlike the novel the episode is adapted from, this is the only plot going on. During the episode a Yeerk takes advantage of her amnesia to try to get her infested, leading her friends to worry she's giving up. Sadly this is reduced to a find Rachel/restore her memory in seconds plot.
In that episode it's revealed that the conspiracy theorist/previously infested woman from the cabin is stalking/watching them. More then a few viewers wish she'd returned, or even joined the team.