In her monthly column, YA of Yore, Frankie Thomas takes a second look at the books that defined a generation.

How do I convey the overflowing surplus of books in the nineties? They had their own aisle in every supermarket and spilled over into the checkout lane so you could impulse-buy them along with gum and nail clippers. Their pages were off-white and delicate as Pringles, their covers so shiny they were almost slimy, and they became polka-dotted by your fingerprints as soon as you touched them. They weighed, and cost, approximately nothing.

What were they about? What weren’t they about? There was a tie-in novelization of every Hollywood movie, plus one tie-in novelization of a tie-in TV show of a Hollywood movie. There was an extremely pink series in which Mary-Kate and Ashley Olsen solved low-stakes mysteries (fictional, presumably, though it wasn’t totally clear). There was a ubiquitous best seller that was just two hundred pages of a little boy being brutalized by his sadistic and increasingly creative mother; then there was a sequel, and another sequel. “You insatiable little book-suckers,” the publishing industry sneered, chucking chicken soup at a dozen newly identified subtypes of soul, “you’ll read anything, won’t you?”

For children’s books in particular it was an era of quantity over quality, an unremitting glut. In those pre–Harry Potter days, a typical “series” meant hundreds of books churned out on a monthly basis by teams of frantic ghostwriters. You could order them by the pound. Often they came with a free bracelet or trinket, as if resorting to bribery. There were 181 Sweet Valley High books, 233 Goosebumps books, and so many Baby-Sitters Club books that their publisher, Scholastic, has never made the full number public (by my count it was at least 345 if you include all the spin-offs)—and they were all, to a certain degree, disposable crap.

But then there was Animorphs.

There’s a certain sound that certain millennials make whenever you mention Animorphs in front of them—a sharp inhalation, a soft “Oh!” No other series from that era elicits such a reaction. Goosebumps and The Baby-Sitters Club are met with self-deprecating laughter and hyperbolic enthusiasm: “I must have read a thousand of those!” But for Animorphs we go quiet, we’re suddenly twelve years old again and we’re suppressing our excitement lest we be teased for caring too much. “Oh,” we say—a hushed confession—“I loved the Animorphs.”

Loving the Animorphs has never stopped being faintly embarrassing. The series ran from 1996 to 2001 and consisted of fifty-four books plus spin-offs, all credited to “K.A. Applegate” (in reality, they were written by the husband-and-wife team Katherine Applegate and Michael Grant, with ghostwriters taking over after Book 25). Like Goosebumps and The Baby-Sitters Club, the Animorphs books were a product of the Scholastic industrial complex, which meant that they looked like disposable crap. If you didn’t read them, it’s probably because you were repelled by their cheesy cover art. It was always a variation on the same theme: a human teenager “morphing,” thanks to primitive computer graphics, into an animal. By stages, a floppy-haired nineties white boy became a jaguar (Book 11); a pretty black girl became a butterfly (Book 19); a statuesque blonde became a giant squid (Book 27). If you flipped the pages quickly, you could make the transformation occur and un-occur via crude flip-book illustrations on the bottom right corner of every page. The entire series seemed to be merely a showcase for these software-generated images, which even then weren’t particularly impressive.

If you’d already judged the books by their covers, their premise was unlikely to change your mind. Even now I hesitate to explain it, because it just sounds so stupid: Earth has been invaded by alien slugs called “Yeerks” that slither into the human ear, take up permanent residence in the brain, and control the host’s body from within. No one on the planet is aware of this extraterrestrial threat except five teenagers—Jake, Rachel, Cassie, Marco, and Tobias—who have conveniently acquired the magical power (I mean, you know, “alien technology”) to transform into animals. Somehow, in between school and homework and trips to the mall, our heroes find time to wage battle against the Yeerks, a job involving frequent travel to the Amazon rainforest, the North Pole, the deep sea, outer space and, once, the Late Cretaceous period. Their secret is never discovered by anyone. Also, they have an alien sidekick named Ax, a blue centaur who’s obsessed with cinnamon buns.

Look, I know! I know how it sounds. And yet, against all odds, the books were great. They were dark and witty and thrilling, endlessly inventive and achingly sad. They made me laugh out loud and cry myself to sleep. I’ve been thinking about them for twenty years.

I’m not the only one. In recent years there’s been a steady trickle of belated critical attention to Animorphs. Those articles, this one included, bear the burden of proving that the series was not disposable crap—even though, yes, it looked like disposable crap and sounded like disposable crap and was made into an inexplicable live-action Nickelodeon TV show that was disposable crap. There’s something about this intellectual exercise that regresses us all to petulant twelve-year-olds at the supermarket, insisting to our skeptical parents that these books are not stupid, they’re educational and totally worth $3.99, please, please, please!

Consequently, today’s Animorphs apologias share a tendency to assert that the series wasn’t really about five teenagers morphing into animals to fight aliens—that it was really about something else, though there’s no consensus on precisely what. Matt Crowley of the AV Club argues that the whole thing was a metaphor for puberty. Meghan Ball of Tor and Lindsey Weedston of The Mary Sue play up its feminist message. Tres Dean of Geek.com claims that Applegate was a “prophet” whose books anticipated 9/11 and the Iraq War. Many fans, including me, find a compelling transgender narrative in the character of Tobias, who chooses to remain in the body of a red-tailed hawk forever rather than continue living as a boy. In drafting this essay, I briefly considered making the argument that the series was really about the experience of being a child inappropriately entrusted with an adult secret.

None of these readings are wrong. But none of them feel exactly right to me, either—not as an explanation of what made the books great. I don’t think we loved them for their allegorical resonance. We loved them because they were exactly what they appeared to be: a series about five teenagers morphing into animals to fight aliens.

It felt so real. No matter how preposterous the plots became, the writing always remained utterly true to the emotional and psychological reality of the characters’ situation. Each book opened with the narrating Animorph (a term the characters themselves disliked and used only with wincing irony) addressing the reader directly. “My name is Rachel,” they began, or “My name is Marco”—and then, apologetically, they explained that they couldn’t tell you their last name, or their exact age, or their location; it was too dangerous. They shouldn’t be writing this at all, really, but they were risking it because the fate of the world was at stake. The sense of urgency was palpable and convincing; it was a remarkably effective narrative technique. (Jean Guerrero of LitHub admits to believing, as a child, that the books were nonfiction.)

Jake, Rachel, Cassie, Marco, and Tobias exist in my memory as real people who endured unspeakable horror. I may not remember the details of the Animorphs’ trip to the rainforest, but I recall with absolute clarity the crushing dread suffered by Jake, the reluctant leader with the weight of the world on his shoulders. I don’t remember why Rachel had to morph into a giant squid, but I will never forget Rachel herself, the popular fashionista turned unstoppable killing machine—how much she loved the war, how deeply disturbed she was by her own newfound bloodlust, how her fellow Animorphs increasingly relied on her to do their dirty work even as they quietly speculated that she was a psychopath. (She’s the character who tends to get invoked nowadays as a feminist role model, a flattening oversimplification that I think does her a disservice.) I still can’t decide whether Cassie, the idealistic pacifist, was brave or naive for sympathizing with the Yeerks and occasionally trying to compromise with them. I still choke up when I think of Marco, who discovered that his mother’s body was possessed by the highest-ranking Yeerk and that he would have to kill her. (“I love you, Mom,” he whispered as he pushed her off the cliff. My heart!) I could talk about all of this forever.

But if you didn’t read them in the nineties, I have little hope of convincing you. The books are long out of print. You can dig up crumbling old copies here and there, but I doubt you’ll see past the sans serif font, the barrage of sub–Star Trek sci-fi babble (Kandrona rays, Gleet BioFilters, Z-space transponders), the cartoony onomatopoeias littering every page—hawk-Tobias screeching Tseeeer!, Yeerk laser blasters going TSEEEW! TSEEEW!, our heroes constantly screaming “AAAAHHH!” Can I really demand, in good conscience, that you read fifty-four of these? Even if you did, it wouldn’t replicate being twelve years old at the supermarket in 1998 and reveling in the sheer abundance of it all. These books were designed for that twelve-year-old, not for you. They were made to be disposable.

To be an Animorphs fan today is to witness for a cult religion that will never gain another convert. We live in a different world now, a world in which publishers pay a single author to write a handsome show horse of a hardcover once a year, rather than employing dozens of ghostwriters to crank out flimsy assembly-line paperbacks all day long. In such a world, Animorphs will always fall short of the aesthetic standard set by Harry Potter and The Hunger Games. This is unfair, since by many other standards it’s the superior series. It certainly deserves its own movie franchise. But as the Animorphs knew too well—as all twelve-year-olds know—life isn’t fair.

The mystery of Animorphs is not why it’s been forgotten, but how it managed to be so good in the first place. How did it happen that the Scholastic factory, grinding out book after book after book, squeezed out a diamond amidst the coal? What made Jake, Rachel, Cassie, Marco, and Tobias leap off the page and stay with us forever? I’m about to get a graduate degree in fiction and I still don’t know how that part works. I know it’s no likelier to happen in literary fiction than in science fiction, or children’s fiction, or fiction written very quickly for a faceless corporation. As far as I can tell, a novelist has very little control over the aliveness of her characters: either they spring to life on their own, or they don’t. I’m grateful to Applegate et al. for showing me that all you can do—all any writer can do—is write. The rest is alien technology.

Read earlier installments of YA of Yore here.

Frankie Thomas is the author of “The Showrunner,” which received special mention in the 2013 Pushcart Prize Anthology. Her writing has also appeared in The Toast, The Hairpin, and Vol. 1 Brooklyn. She is currently studying fiction at the Iowa Writers’ Workshop.