- Narrator: Tobias
Tobias volunteers himself to be captured to discredit the Anti-Morphing Ray.
Tropes:
- Agony Beam: The torture device works mentally, meaning Tobias is forced to relive a mish-mash of his worst memories. He responds by hiding within his hawk mind, which can comprehend pain, but not human suffering. Sub-Visser 51 responds by alternating between pleasure and pain, luring Tobias out of the hawk with things that appeal to his sentient mind and then forcing him to feel the pain before the hawk can shield him.
- Alpha Bitch: Taylor was one before the house fire that disfigured her.
- Ambiguous Situation: The Animorphs never learn if the Anti-Morphing Ray works or not, as neither they nor Visser Three are willing to be its test subject.
- Becoming the Mask: Taylor and Sub-Visser 51, on both ends. Sub-Visser 51 fell in love with Taylor's lavish and attention-seeking lifestyle, while Taylor found thrills in being a Torture Technician. The two of them alternate between "I" and "We" pronouns, even though it's always Sub-Visser 51 talking.
- Cold-Blooded Torture: Tobias is subjected to this at the hands of Sub-Visser 51 in order to get him to "demorph".
- Deal with the Devil: After a house fire disfigured her, Taylor was approached by the Yeerks. They wanted her mother, a police chief, as a host, and promised to give Taylor her looks and limbs back if she agreed to help them. She did, and the Yeerks rebuilt her body with plastic, infested her with Sub-Visser 51, and sent them to capture her mother.
- Dying Dream: Tobias sees a memory belonging to Elfangor when his torture reaches a critical point. Ax claims it was an Andalite spiritual rite called an Utzum.Ax: Certain medicine men believed they could pass memories through DNA. Legend says these memory messages are triggered by imminent death. A surge of strength during the last moments to ease their passage. Ancient superstition.
- Evil Counterpart: Tobias sees Taylor as Rachel's, since they're both beautiful blonde girls with a disturbing love of blood and violence. While Rachel tries to point herself in the right direction, Taylor and Sub-Visser 51 are sadists who don't care about morality and just want others to suffer.
- Fallen Princess: Taylor was once the Homecoming Queen and a tennis champion. A house fire robbed her of her looks, and her "friends" along with it.
- If You Kill Him, You Will Be Just Like Him!: Tobias begs Rachel not to kill Taylor, as he sees too much of Rachel in Taylor to accept Rachel acting like Taylor.
- Impersonation Gambit: To sell to the Yeerks that they've captured an Andalite, Tobias acquires and morphs into Ax.
- The Needs of the Many: Cassie is taking care of a terminally ill bald eagle at the beginning of the book. When no good option to rescue Tobias becomes available, the other Animorphs place the eagle where the Yeerks will find it, hitch a ride as fleas, and jump off when they're inside the facility. The eagle ends up being fed to Taxxons in an attempt by the Yeerks to break Tobias.
- High-School Dance: The book opens with another one, where Rachel explains to Tobias that she needs to do things like this to remember that she's still a teenage girl. Things get complicated when her stalling nearly re-traps Tobias in human morph.
- Stockholm Syndrome: Tobias feels pity for Taylor even after she tortures him, reasoning that her situation made her easy prey for the Yeerks.
- Torture Technician: Sub-Visser 51 specializes in torturing enemies of the Yeerk Empire.
- Wide-Eyed Idealist: Tobias finds that the Andalite's natural instincts are heavy on optimism. Ax is somewhat amused, then explains that the Andalite warrior culture trains them for realism.
- Wrong Context Magic: As Tobias's Shapeshifter Default Form is a hawk, the Anti-Morphing Ray will have no effect on him if it works. This is why he volunteers to be its test subject. At the end of the story, Sub-Visser 51 is confused by how Tobias can still "demorph" back to Andalite after the two hour time limit is up.
- You Have Failed Me: The Yeerk scientists who built the Anti-Morphing Ray are fed to Taxxons when it fails to make Tobias "demorph".
