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"You're saying because I acquired that crocodile I lost control of my morphing powers?"
all control. Just some. [...] You've been having an allergic reaction to the crocodile DNA."
Rachel and Ax[src]

The Reaction, published in October 1997 and written by K.A. Applegate and Michael Grant, is the twelfth book in the Animorphs series. It is the fourth book narrated by Rachel and her third book as sole narrator.


Official Description

Rachel's got some pretty strange stuff happening. She can't control her morphing. One minute, she's doing homework. The next, she's morphing a full-grown crocodile, and -- without returning to human form -- she becomes an elephant. That's when the floor gives way and Rachel finds herself looking up at what used to be the kitchen ceiling.

What's going on? No one's sure, but Rachel and the other Animorphs have to figure it out -- quickly. Because if someone sees Rachel's out-of-control morphing, the other Animorphs and Ax are in for some serious trouble...

Plot Summary

This section needs a rewrite
Book 12 inside cover

Rachel in the crocodile enclosure

Rachel and Cassie are at The Gardens on a field trip when Rachel sees a little boy climb the railing and falling into the crocodile pit. Cassie goes to get help, but without first telling Rachel not to do anything stupid. One of the six crocodiles in the exhibit eyes the boy, and Rachel jumps into the pit to save the boy, but soon discovers that there's another much bigger crocodile inches away from them. The crocodile charges and Rachel avoids its jaws and lands on its back. As it tries thrashing her off, she quickly grabs its sides and acquires its DNA. She decides to then morph into the crocodile and fight it. After using human intelligence to defeat the croc, Rachel thought-speaks to the boy and get him to ride on her back to safety.

Later, after being chewed out by Jake for what she did, the Animorphs talk about how The Sharing is hiring a teen heartthrob named Jeremy Jason McCole to be their spokesman, which would get many girls to join The Sharing, and they have to stop that, but Rachel and Cassie are excited because they get to meet Jeremy Jason McCole.

That night, while doing her homework, Rachel goes online to check out Jeremy Jason McCole and discovers he'll be in town in a few days on a talk show called the Barry and Cindy Sue Show. Suddenly, after telling Cassie the news, she sees her hand turning green, she starts morphing into the crocodile and she can't stop it. She tries demorphing, but instead of becoming human again, she's now morphing into a fly, but then starts morphing into an elephant, causing the floor of her room to collapse and crash into the kitchen. She morphs back to human just as rescue workers dig her out and take her to the hospital, whereafter reporters find out she's also the girl that jumped into the crocodile pit. Rachel's dad Dan drops in after hearing everything that happened. Rachel then decides to ask her dad to get her on the Barry and Cindy Sue Show, so that way, they can get to Jeremy Jason McCole.

After leaving the hospital, Rachel goes to stay with her dad at a hotel suite, she calls Cassie to come over, and deciding that they need to talk to Ax about what's going on with her. The next day at school, Rachel is called to Chapman's office, which makes her nervous because he might have suspected something. He talks to her about all the recent stuff and if there's anything going on with her, he even offers her the choice of joining The Sharing. Suddenly, she sees her shoes tearing up as her feet become grizzly bear feet. Chapman then sends Rachel back to class, but not without noticing her feet commenting on it being boots.

After school, Rachel meets up with the others in the sky above the beach in their seagull morphs and Ax in his harrier morph. They fly towards the ocean to a yacht where Jeremy Jason McCole is with his producer, a woman, and a man. Rachel and Cassie hear him talking about doing more serious roles and stop being a goody-good teen heartthrob. The man tells Jeremy Jason McCole that he can get anything he wants, just by representing The Sharing, and he won't say no to it. It was then Rachel and Cassie realize the man is really Visser Three in human morph.

Suddenly, Rachel starts morphing out of control again, this time she was growing an elephant trunk, which sends her down into the water. Now full elephant, Rachel starts swimming back up, but she's too far down to make it to the surface, Jake and Cassie in their dolphin morphs and Ax in his shark morph arrive to help, but then, Rachel starts rapidly shrinking and is now inside an air bubble as an ant. Marco reports that Visser Three is morphing.

Rachel begins morphing again, this time into her crocodile morph. They soon hear a loud splash and Marco tells them it was Visser Three, he had just finished morphing into something that can shoot spears from its mouth. Ax tells them its an aquatic creature called a Lebtin Javelin Fish. They spread out and when Rachel goes up to breathe, she sees Jeremy Jason McCole admiring everything he just saw, which makes Rachel really mad. Visser Three fills up with water, and fires a spear and hits Rachel through her tail. A second spear is fired at Cassie, almost impaling her. Rachel then comes up with a plan, she plays dead and goes belly up, and when Visser Three is close enough to her, she uses her powerful jaws to chomp right into the Visser, popping him and sending him flying through the water. Marco then shows up in his dolphin morph, a little too late.

Later, Ax explains to the others that Rachel's out-of-control morphing is because she has an allergic reaction to the crocodile morph that she acquired, and her emotions are what sets it off, (affection from looking Jeremy Jason McCole on the internet; fear from being in Chapman's office; and anger from seeing Jeremy Jason McCole making the deal with the Yeerks and being a superficial jerk.) Ax says the only way to cure the allergy is a natural process where Rachel will 'burp' the DNA so to speak, forcing out the crocodile morph in its entirety and expelling it from her system, a process Andalites call hereth illint.

Jake tells Rachel to keep a low profile, which also includes not going on the show, but the next day at school, she lies to Jake and Cassie saying the hereth illint happened. After school, Rachel takes a cab to her dad's hotel, where they walk together to the TV studio, Cassie meets up with them when a llama runs past them with its handlers chasing it. As the make-up artist is dealing with Rachel's hair like tugging it, her hair starting becoming wolf fur. Cassie gets the make-up artist to leave long enough for Rachel to calm down. Just then, Jeremy Jason McCole appears and rudely tells them to leave. Outside, they bump into the llama, only to find out its really Marco, he had hidden the real llama after acquiring it and says Jake and Ax are also there in insect morphs. After Cassie tells Marco what Rachel did, they decide as a backup, someone should acquire and morph Rachel. As the trainers take Marco onto the stage, Cassie acquires Rachel's DNA.

Suddenly, after being escorted to the green room, Rachel starts becoming sick. The hereth illint was now starting and the crocodile's mind takes over Rachel's human body and goes crazy. As Cassie takes Rachel away, they see that process of expelling the DNA is that the crocodile is coming out of Rachel's back. They get into a restroom, just as Rachel starts morphing into a grizzly bear. Just as Cassie morphs into a squirrel, Rachel had finished "burping" the crocodile out of her, the crocodile eyes her and lunges, but Cassie jumps on its head, attacking its eyes and they crash out of the restroom and head for the backstage and causing hysteria. Marco slips on the floor and knocks Jeremy Jason McCole off his and was now face to face with the crocodile. After being frozen in horror, he now screams just as Cassie kills the lights and Ax kills the crocodile. As the Animorphs run for it, Rachel steps on something that felt warm and squishy; it was the Yeerk that had infested Jeremy Jason McCole.

Rachel goes back to find Cassie, she finds a man talking to another Rachel, who was actually Cassie. The real Rachel hides and as Cassie leaves, the man yells "Andalite!", but Cassie replies with "Yeah, a light would be helpful, too", thereby dispelling the man's suspicion, and meets up with Rachel. Two days later, the Animorphs are in the hotel room watching the news saying Jeremy Jason McCole has fled to Uzbekistan, and they know he will no longer have anything to do with the Yeerks or crocodiles.



Supporting Characters:


Other Characters:



Major/Highlighted Events

  • After witnessing a kindergarten boy fall into a crocodile pit at The Gardens, Rachel jumps in to save him, acquiring and morphing the crocodile. However, she feels nauseous upon acquiring the crocodile DNA and learns later on that night that she cannot control her morphing, which causes her to morph into the crocodile, a housefly and an African elephant in her bedroom, all without demorphing back to human, and ends up destroying her house.
  • It is revealed that morph-capable individuals can be allergic to the DNA of particular animals, in this instance being Rachel's allergy towards crocodiles. Ax explains that Rachel must go through a hereth illint, a process which involves her body expelling the offending DNA by creating a crocodile entirely out of the spare mass in Z-space. Rachel successfully manages to eliminate the crocodile DNA from her system, thus rendering the morph unusable, while Ax kills the crocodile.
  • Cassie acquires and morphs into Rachel, making her the first human Animorph to acquire and morph into another human.


Morpher Morphs acquired Morphs used
Jake -- Seagull, Bottlenose Dolphin, Cockroach
Rachel Crocodile Crocodile, Housefly, African Elephant, Grizzly Bear, Seagull, Black Garden Ant (possibly), Termite (possibly), Bald Eagle (partially), Wolf (partially)
Cassie Human (Rachel) Great Horned Owl, Seagull, Bottlenose Dolphin (Monica), Squirrel (Magilla), Human (Rachel)
Marco Llama Seagull, Bottlenose Dolphin, Llama
Ax -- Northern Harrier, Tiger Shark, Housefly, Human (Main)
Visser Three Lebtin Javelin Fish Human, Lebtin Javelin Fish


  • The front cover quote is "Trust no one...."
  • The inside front cover quote is, "Nothing like a crocodile's smile...."
  • The character Jeremy Jason McCole is a parody of Jonathan Taylor Thomas, and The Barry and Cindy Sue Show is modeled after Live with Regis and Kathy Lee.
  • Cassie's mom (Michelle) thinks Cassie is interested in a number of musical groups: The Fudgies, Snoopy Diggity Dog, Boys Eleven Men, and Nice Is Neat.
  • This book takes place a few months after The Stranger, as Rachel mentions how she spends time with father most months after he had moved out of state.
  • The book is also set a month or so after The Android, as Chapman mentions the mountain lake waterskiing trip, with Rachel mentally remarking that the Animorphs were present in morph.
  • Rachel internally states that she has a bit of a grudge after Chapman tried to kill her, referencing The Visitor.
  • Despite the Animorphs being unable to go from one morph to another, as Ax confirms, Rachel is able to do so while being allergic, thereby proving that the ability to pass from one morph to another is not impossible.
  • Cassie acquires and morphs into Rachel, making her the first human member of the Animorph to acquire another human. If one counts Ax as an Animorph and his acquiring of the human members' DNA in The Message as separate acquisitions, this marks the sixth time that an Animorph has acquired a human, as well as the sixth time that one of them has acquired a member of their team. It is also the second time Rachel has been acquired, and the third instance that one of them has morphed another Animorph, if Ax's three-day masquerade as Jake is counted as one instance.
  • Ax's shark morph, previously unspecified, is revealed to be a tiger shark.
  • The "Brad Pitt Montana movie" mentioned by Marco is the 1994 film Legends of the Fall.


  • Despite it being a book narrated by Rachel, she is referred to in the third person on p57.
  • When Ax notifies Jake that Rachel has morphed from African Elephant to an insect without demorphing, Jake cries that it is impossible; however, he had just witnessed Rachel go from seagull to elephant less than a minute ago.
  • Rachel states that because she is best friends with Cassie and knows Cassie's mother, she has access to The Gardens whenever she wants. However, in The Invasion and The Message, Cassie makes it clear that the zoo only allows her free admission because she is the daughter of the head vet, and that everyone else must pay to get in.
  • In this book Cassie mentions that she told her mother NIN stood for 'Nice Is Neat', so she could get the new Nine Inch Nails CD. However, in real life NIN hadn't released an album since 1994 at that point, and the series makes it clear that it is set post-1995.
  • Rachel's mother, Naomi, steps out of the house to buy some milk. However, when Rachel falls into the kitchen a few minutes later, she remarks that a gallon of milk is leaking from the fridge.

TV Adaptation

The Reaction was adapted as part of the Animorphs TV series, which aired on Nickelodeon and YTV between the fall of 1998 and the spring of 2000. The twelfth book in the series was covered by the eleventh episode, "The Reaction". The TV episodes did not follow the books faithfully, altering many aspects of the characters' roles within the Animorphs, the events in the war against the Yeerks, and added plot lines that were not present in the books.

Changes from Book to Episode

Animorphs reaction tv show larry and linda live

The web site front page for Larry and Linda Live

  • This story was used as an TV series episode (given the same title and using the same animal, the crocodile) but the episode had Cassie allergic to the morph rather than Rachel in the books; also, the allergy simply caused Cassie to morph randomly between her human and crocodile morph, rather than the random transformation from one morph to another that was demonstrated in the book.
  • In the book series, Rachel had the allergic reaction to the crocodile, but on the show, they changed it so that Cassie was the one that acquired the crocodile and eventually "burped" out of her system.
  • In the book series, the Yeerk that was controlling Jeremy Jason McCole was killed when Rachel stepped on it, but on the show, they changed it so that the Yeerk was eaten by the crocodile.
  • The crocodile that was used in the episode was smaller than the one in the book, which made it less dangerous for the cast and crew, and easier to handle for the trainers.
  • In the book, the show Rachel goes on is called the Barry and Cindy Sue Show, in the TV series, the show is called Larry and Linda Live.


U.S. Images

International Covers


Main Series #1 The Invasion | #2 The Visitor | #3 The Encounter | #4 The Message | #5 The Predator | #6 The Capture | #7 The Stranger | #8 The Alien | #9 The Secret | #10 The Android | #11 The Forgotten | #12 The Reaction | #13 The Change | #14 The Unknown | #15 The Escape | #16 The Warning | #17 The Underground | #18 The Decision | #19 The Departure | #20 The Discovery | #21 The Threat | #22 The Solution | #23 The Pretender | #24 The Suspicion | #25 The Extreme | #26 The Attack | #27 The Exposed | #28 The Experiment | #29 The Sickness | #30 The Reunion | #31 The Conspiracy | #32 The Separation | #33 The Illusion | #34 The Prophecy | #35 The Proposal | #36 The Mutation | #37 The Weakness | #38 The Arrival | #39 The Hidden | #40 The Other | #41 The Familiar | #42 The Journey | #43 The Test | #44 The Unexpected | #45 The Revelation | #46 The Deception | #47 The Resistance | #48 The Return | #49 The Diversion | #50 The Ultimate | #51 The Absolute | #52 The Sacrifice | #53 The Answer | #54 The Beginning
Megamorphs The Andalite's Gift | In the Time of Dinosaurs | Elfangor's Secret | Back to Before
Chronicles The Andalite Chronicles | The Hork-Bajir Chronicles | VISSER | The Ellimist Chronicles
Alternamorphs The First Journey | The Next Passage
TV Tie-Ins Meet the Stars of Animorphs
Graphic Novels #1 The Invasion | #2 The Visitor | #3 The Encounter | #4 The Message | #5 The Predator | #6 The Capture