My Teacher Is an Alien is a series of four children's novels by Bruce Coville comprised by:
- My Teacher Is an Alien
- My Teacher Fried My Brains
- My Teacher Glows in the Dark
- My Teacher Flunked the Planet
The series is about Peter Thompson, a nerdy boy, and his best friend Susan Simmons who find out that their new teacher, Mr. Smith, is actually an extra-terrestrial agent named Broxholm. They suspect an Alien Invasion, and work to expose the infiltrator. In the second book in the series, Duncan Dougal, the class bully and a side character from the first novel, discovers that there is another alien posing as a teacher, and that he has been the subject of an alien experiment to expand his intellect.
Book three completely changes gears, as Peter discovers that the aliens are not necessarily dangerous and ends up living with them as a guest on a gigantic alien exploratory vessel. He learns that Broxholm had been sent by an alien council who has decided to put Humanity on Trial to find a proof whether or not Humans Are the Real Monsters. In the final installment the kid and alien characters team up and embark on a research mission to explore the nature of humanity and determine whether the earth can be saved.
The narrator changes character in each of the books, following Susan in the first as she attempts to find proof of Broxholm's supposedly "evil" plans (abduct 5 students and take them back for study, not realizing his true intent was to use them as proof that Earth can be redeemed), then Duncan in the second as he tries to prove one of his teachers in middle school is an alien, then finally Peter in the last two. The last two books were originally planned to be one longer book, which is why Peter is used as the narrator twice. The "switching narrator" technique is one Bruce Coville would later use in other books.
The first book was also adapted into a video game by 7th Level and Byron Press Multimedia company.
This series features examples of:
- 90% of Your Brain: A major concept in the series is that humans supposedly would be the most intelligent species in the universe if only we used all of our brains.
- Abusive Parents: Duncan's parents, but more so with his father. As revealed in ''My Teacher Fried My Brains", his brother bullies him and neither his parents do nothing about it. Although his mother is a bit kinder, though not much more supportive, his father whacks him too, although in all fairness, both sons receive the same treatment at times. His father says it toughens him up in life. This is likely Duncan's Freudian Excuse for becoming the class bully.
- An Aesop: Pay attention in school, kids. Because your teacher might be an alien trying to prepare humanity for the galactic stage. More generally, that education is important for individuals to better themselves, and in turn better society.
- Alien Among Us: Broxholm in the first book, Kreeblim in the first two (though readers don't find out until the second), and multiple cases in the fourth. Apparently, the aliens investigating Earth bought several pieces of property so they could blend in, with multiple redundancies if need be.
- Alien Non-Interference Clause: In the last book the kids and the aliens are under specific instructions only to observe human behavior and not to interfere in any situation. Predictably, a Screw the Rules, I'm Doing What's Right! situation eventually presents itself. Specifically, a woman is being tortured right in front of them with a torture method the protagonists refuse to even describe to the reader, although given the context, an older reader might make an educated guess that it amounted to rape. Broxholm gets so pissed off that he knocks out the torturer and carries the woman to safety. Ultimately, the solution presented for the problem of "What do we do with the human race?" involves averting this trope: Send more aliens to Earth as teachers and guides, helping humanity build up from its current state until they are finally ready for greater galactic society. This process also involves rebuilding the mental unity humans used to have, the fracturing of which is part of why we're not so good at peace.
- Aliens Are Bastards: Zig-zagged, although they are well-meaning and mostly peaceful, some of the aliens do want to destroy Earth because of their somewhat justified belief that Humans Are the Real Monsters.
- Alliterative Name: Susan Simmons and Duncan Dougal.
- Ascended Extra: Duncan goes from a minor supporting character in the first book to being the protagonist of the second and goes through the biggest arc by the series end.
- Benevolent Alien Invasion: One of the possibilities being considered to deal with the Earth problem is to take over the planet outright so that humans can be given the tools they need to end wars, eradicate disease and poverty, etc. in a controlled fashion while making sure the tools aren't abused.
- Berserk Button: Peter's Establishing Character Moment shows him as a spineless nerd who lets Duncan push him around without resistance... unless you mistreat his books. Then he fights back.
I was a little surprised when he tossed Peter's book into the puddle. Even Duncan should have known that was something you just don't do to Peter.
- Big Red Button: The beginning of My Teacher Flunked The Planet showcases Broxholm indicating a very prominent button on the starship New Jersey. The Button (as Peter calls it later) is inactive at the time, but if the proper series of codes are input to make The Button active, when pushed, it is capable of reducing Earth to stardust.
- Bizarre Alien Sexes: The series mentions one species that requires "five different genders just to get an egg-and three more to hatch it".
- Bizarre Sexual Dimorphism: Subverted. The human protagonist assumes this after meeting Kreeblim, a female alien who looks very different to the previously introduced male alien, Broxholm. It turns out that they are of completely different species.
- Brilliant, but Lazy: Peter starts out this way, but begins unleashing his knowledge when he learns it might help foil the alien plot. He does so even more as a Plan B, because he wants to see the stars.
- It turns out that Duncan is this way too, until the brain fryer unlocks his brain's true potential. According to the aliens, the same is true for all humans, as they have the largest (and least used) brains in the universe.
- Brutal Honesty: Broxholm comes off as tactless and rude. As it turns out, however, on his planet being brutal with honesty is normal (although Broxholm describes it as just telling the truth and then getting on with things), and in fact in comparison to the rest of Broxholm's kind, Broxholm is a "pussycat". But even the "pussycat" Broxholm cannot understand what he sees as the humans' obsession with talking nicely all the time.
- The Bully: Duncan starts out as this.
- Butt-Monkey: The fate of Duncan starting from the second book.
- Cassandra Truth: Generally averted. The kids realize that no one will believe their story about aliens, so they don't bother alerting the authorities.
- Played straight during Duncan's period of hyperintelligence. Putting his enhanced mind to such problems as world hunger and the energy crisis, he develops plans to solve all of these and sends them to various authorities, who basically ignore him.
- Peter's father initially doesn't believe the stories that Peter went to space with the aliens, and spends a great deal of time in the second book searching for him. It's not until he meets up with Ms. Schwartz in the fourth novel that he finally accepts the truth.
- Cerebus Syndrome: The last book takes a really heavy turn as the kids and the aliens examine the worst in human nature. Particularly traumatizing is a chapter about starving third world villagers.
- Children Are Innocent: The aliens believe this, and theorize that earthling children will be able to provide better perspective on humanity because they have not yet become jaded and cynical.
- Cloud Cuckoolander: Peter, along with most of the aliens.
- Cool Teacher: Betty Lou Karpou a.k.a. Kreeblim and Ms. Schwartz.
- Covers Always Lie: The first book shows Broxholm unmasking at school, which he would never risk doing so in a public place, and then subverts it in the climax when he's coerced into it by Susan repeatedly playing "Stars and Stripes" on her flute. The second book implies that Duncan is going to have his brain fried as if he were in an electric chair, when what the device doing the "frying" really does is give his cognitive abilities a serious boost. The fourth book, though, is the worst offender. It shows Broxholm threatening to push The Button that will destroy the Earth while Susan and Peter are about to attack him. In reality, Broxholm and the kids are working together in a desperate attempt to prevent the Earth's destruction.
- Crapsack World: The kids (and the readers) take a tour of it in the fourth book, as they discover the problems going on in the impoverished or corrupt parts of Earth.
- Crying Wolf: In the second book, everyone believes that Duncan is lying about there still being an alien stationed in their town, especially after he pulls a false fire alarm on his first day of seventh grade (people thought that another alien attack was about to happen when the alarm went off).
- Crystalline Creature: The Captain of the New Jersey is a loose collection of limb-sized crystals that float freely in a tank of liquid and communicate through tinkling music, an uncommon body type even among the hugely diverse crew.
- Darker and Edgier: The fourth book features a lot of preaching about Earth's problems, along with portrayals of things such as people tortured for disagreeing with their government, people starving, and many more, while suggesting that the only way to prevent Earth's bad behavior is to nuke it out of existence.
- Deliberate Under-Performance: Played with; Peter informs the kids in school that aliens are going to kidnap 5 students: the best, the worst, and the three most average. This causes immediate chaos, with the top students deliberately trying to get in trouble or flunk tests; the worst students and troublemakers suddenly sucking up to the teachers, and mediocre kids paralyzed by uncertainty not knowing how to avoid being one of the three most average. And inverted with Peter himself; he begins to perform above his usual standard as a "Plan B" so that if the kidnapping does happen after all, he's more likely to be one of those selected.
- Didn't Think This Through: Hoo-Lan's attempt to slow human technological advancement (which to alien eyes had far outpaced social advancements) by introducing television. It just accelerated it, while slowing down social development even more. Given the current (im)balance between technology—like the Internet, smartphones and social media— and social norms, he had cause to be concerned.
- Dirty Business: Broxholm indicates that even those who are leaning toward the destruction of Earth only do so because they don't believe the other options will work. They would not celebrate the destruction of a world and its people, but mourn it deeply.
- Disappeared Dad: Peter's own father never knew HIS father.
- Earth Is the Center of the Universe: Played with. Earth is insignificant at the moment. However, Humans Are Special in that they are more violent and destructive than other species. Earth is the center of an ongoing debate between every other intelligent race in the universe about that fact.
- Earth-Shattering Kaboom: It may come to this.
- E.T. Gave Us Wi-Fi: Hoo-Lan is revealed to have influenced history throughout centuries, with more or less success. He is feeling especially guilty about being responsible for the invention of television. TV was intended to distract people and slow technology growth until humanity had matured a bit more. It didn't end up doing anything but delay said maturation.
- Extra Parent Conception: The series mentions one species that requires "seven genders [sic] to produce an egg, and three more to hatch it". This being a kid's book, the exact mechanics of this are never explained.
- Face–Heel Turn: Averted with Peter in a huge way. See Hero Antagonist below.
- Fantastic Racism: Played with. Even the most vehemently anti-human aliens acknowledge the worth and value of individual humans, but it's hinted that many of them apply very broad generalizations to populace as a whole.
- Partially justified, however, for two reasons: first, some of the raw data the aliens used to draw their conclusions from included humans stockpiling food they then eventually throw away, while children in Third World countries starve, humans making war on each other for petty reasons, humans torturing each other, etc. In fact the protagonist refuses to describe a specific torture method that drives Broxholm to save the torturee, but given the torturee was female it's implied to be rape. Second, the aliens are familiar with non-violent humans, but are also disgusted that the non-violent humans are too apathetic to actually solve global problems.
- Faster-Than-Light Travel: The aliens travel by "folding" space (the details of which are conveniently skirted when the primary alien characters all admit they don't understand the physics of it). They also believe humans will soon discover even faster, easier FTL methods, a possibility which terrifies them.
- The Federation: We never learn much about the alien's government, but it seems that most peaceful, intelligent species are part of a cooperative agency. Unlike most examples of this trope, humans are not a part of the Federation, which of course is the entire point of the story.
- First Day from Hell: Duncan's first day in the second book. He catches all sorts of hell from teachers and classmates alike despite his best efforts to turn over a new leaf. Then he spends hours hiding in a dumpster after pulling a fire alarm on impulse.
- "Flowers for Algernon" Syndrome: Duncan's intelligence boosting "Brain Frying" is temporary, and he will eventually return to ordinary human intelligence. Mildly subverted in that he is now much wiser and knows his potential, so he might find some use for ordinary human intelligence, whereas before he acted like a dimwitted bully.
- Flying Saucer: Lampshaded with a reference that Peter really, really dislikes this term.
- Fold the Page, Fold the Space: A random alien explains the ship's movement using a noodle-like alien food. The book also makes a point that said alien knows the general theory but can't explain the mechanics of how it works, because he's not actually an engineer, much as how most people have only a vague idea of how an internal combustion engine works.
- Foreshadowing: In the first book, Peter speculates that the aliens are afraid that humans will start an interstellar war if they make it further into space. He's right.
- Freudian Excuse: Duncan is a bully because his home life sucks: his older brother bullies him, his father thinks the bullying is healthy, and his mom just doesn't care.
- Genius Serum: The Brain Fryer was thought to be this when used on Duncan Dougal, so much so Duncan starts to fear this will wear off and he'll go back to being a meathead. Kreeblim insists the machine simply unlocks the potential of one's brain, with the flashes of insight and knowledge simply being him finally applying himself.
- Genocide Dilemma: None of the aliens really want to kill off all the humans, but many believe it's necessary for the safety of the galaxy.
- Genre Shift: The first two books are suspense stories about a kid trying to prove a certain teacher is an alien, and stop (what appears to be) an imminent threat. The last two books are far more akin to Star Trek in tone and genre, and reveal that the previous "villains" were actually good.
- Gentle Giant: Broxholm possesses physical strength far beyond that of comparably-sized humans, and packs a laser gun to boot, but he only ever directly harms someone once. In fact, he chooses to be unmasked and jeopardize his mission rather than put human lives at risk.
- The Glasses Gotta Go: When the aliens are putting a translator device in Peter's brain, they take the liberty of fixing his eyesight.
- Good All Along: Broxholm and the other aliens are revealed to be this in the sequels.
- Gray-and-Gray Morality: Are humans bastards or was Rousseau right? The books suggest that neither answer is a simple as it seems.
- Graying Morality: The first book was just about some kids trying to stop an evil alien from abducting people from their class; likewise, Peter's decision to ditch his neglectful father is seen as at least somewhat understandable. The sequels then reveal the aliens' motives and begin to explore how Peter's dad is dealing with his disappearance.
- Green-Skinned Space Babe: Subverted. Although Kreeblim may be green-skinned, female and humanoid, she is not at all attractive by human standards. But she says she's not considered ugly on her home planet.
- Hero Antagonist: Broxholm is the Big Bad of the first book, but becomes one of the main protagonists in the sequels.
- Hero with Bad Publicity: In the second book, Duncan is the only person who can get the word out that there's still an alien spy among the school staff, but because of his reputation as a troublemaker, few people will give him the time of day. Later, when he becomes super smart, he figures out the solution to problems such as world hunger, but because he's a kid, no one will take his ideas seriously.
- Hive Mind: The kids and the aliens eventually discover that the entire human race was once a hive mind, but that we forcibly isolated our minds from each other because of the incredible strain created by the swelling population. Our violent ways are the result of subconscious trauma that comes of not being connected to one another as we're designed to be.
- Hidden Depths: Duncan starts off as a Jerkass bully character but eventually grows into a more well-rounded character.
- In the end, the entire human race turns out to have Hidden Depths that many of the aliens did not give them credit for. We're capable of senseless war, but also of risking our lives for our fellows, for example.
- Humanity on Trial: One of the main plot points of the series in the last two books.
- Humans Advance Swiftly: A big part of the plot. Most species have settled down into peaceful coexistence long before they have the technology to make weapons that pose an existential threat to themselves, but humans shot from the stone age to the atomic age in a ludicrously short period of time. From the perspective of other species humans are culturally a barbarian horde with nuclear weapons, and there's a very real fear of humans discovering effective space travel in the near future.
- Humans Are Special: Averted in one respect, but also played straight — the third book mentions that our technological progress has been much faster than most/any alien race's, and it's theorized that this is a reason our civility is not on par with other spacefaring races (it hasn't "caught up" yet). Also, turns out we're naturally telepathic, or were, and could be again.
- Humans Are the Real Monsters: Many of the aliens think this, and show some of the evidence to the protagonists. Determining whether this is in fact true is the task of our heroes in the final book.
- Humans Are Warriors: This is the big reason the other races are worried; largely due to how fast human technology advances, humans kept their full aggression and tribal thinking even after developing weapons that could sterilize a world with no signs of changing any time soon.
- I Know You Know I Know: Susan and Broxholm play this game in the first book. Broxholm implies that he knows Susan was in his house, which indicates that he knows that Susan knows that he is an alien.
- In Your Nature to Destroy Yourselves: So naturally the antagonistic aliens would like to destroy us first so they don't get caught in the mess. And even those who advocate leaving humanity alone generally do so because they believe that humanity will destroy themselves before they become a threat.
- Jerkass Realization: There's a lot of attention devoted to the fact that the protagonists (and the similar-aged readers by proxy, which is deliberate on the author's part) have comparatively easy lives when compared to all the suffering of humans abroad. Peter gets one when he sees the fact that Americans stockpile food and throw perfectly good food away if they have too much, while children around the world starve, and Peter is very uncomfortably reminded of the time when he got mad at his father for not having enough snacks in the house to keep him fed until dinner. Susan gets one when it's explained to her that contrary to what she previously thought, the humans can very easily solve all their problems if enough of them want to, the problem is not ability but apathy. This makes Susan mad enough that she resolves to do something about the world when she grows up, possibly even becoming a leader.
- Jerk with a Heart of Gold: Broxholm and Duncan. Averted with Big Julie, who Peter continues to dislike even after the big guy softens up a little and admits to liking him. Which is understandable, as Big Julie's affection for individual humans does not change the fact that he is in favor of destroying the planet.
- Kill All Humans: Some aliens suggest this as the only solution to humanity's violent nature. Hey, at least they feel bad about it: when asked, one of the aliens explains that if they blow up the humans, the aliens will certainly not be singing songs about their glorious conquest that they won; instead, if they actually kill all the humans they will spend their time afterwards miserable and sorry that it had to come to that, mourning over what was lost and what might have been.
- Knight Templar: The aliens who want to destroy Earth for the safety of the rest of the galaxy.
- Kryptonite Factor: Broxholm despises human music, which is so painful to his ears that it can incapacitate him. Peter later notes that he had special ear filters installed after the incident at the end of the first book as a counter.
- Latex Perfection: The alien teachers typically disguise themselves as humans with this kind of mask, plus gloves and such. Later, even the main human kids wear them to appear as different children. Justified since they have alien technology—for example, its material can change skin tone automatically.
- Life Isn't Fair: This trope is Duncan's pet peeve at the beginning of the second book, although in this series the phrase is "Life is rough". Interestingly, whether it's justified or not depends on the situation: his family uses it to justify the piss-poor treatment he gets at home, which makes Duncan sympathetic. But it's completely justified when it's said to Duncan at school, because it's used to justify stopping him from bullying others, which he felt was unfair until his character development.
- Living with the Villain: Well, let's see here, the title might be a hint... (even if they turn out to not be evil after all in the third and fourth books)
- Low Culture, High Tech: Humans, from the aliens' perspective. Most races outgrow the need for violence long before they get to humanity's current tech level.
- Mentor Occupational Hazard: Subverted with Hoo-Lan.
- Mile-Long Ship: The alien vessel that Peter boards is called the New Jersey, because it actually is about the size of New Jersey.
- Misery Poker: Referenced and then defied in My Teacher Flunked the Planet. When Peter hears Susan say "Boy, I miss my family" (as they're traveling with aliens and can't see their families, and she can only have occasional phone calls with them) he thinks "At least you have family to miss" (due to him thinking that his father couldn't care less about his disappearance) but keeps silent because he doesn't want to get in a game of "Who's the most miserable".
- Missing Mom: Peter's mom abandoned her family when "someone better came along", and his father lost HIS mom when he was "too old to be adopted", as he put it.
- My Greatest Failure: Hoo-Lan giving television to mankind. See New Media Are Evil.
- My Skull Runneth Over: In My Teacher Fried My Brains, Duncan goes from dumb bully to super-genius after using an alien machine. However, his brain soon begins to pick up information like radio and TV signals out of the air, making it impossible for Duncan to think. Justified: it turns out the alien's plan was to make his brain into a communication device so she could contact her leaders in space.
- My Species Doth Protest Too Much: The human protagonists eventually have to find examples of this trope from their own species, the human race. It's difficult, but eventually they do, one example involves a doctor risking his life in a hellish war zone to save a child whose limbs were blown off.
- Narrative Profanity Filter: Broxholm's reaction to television is "'I spit in deep disgust at your decision to play in your own garbage.' Only the last word wasn't 'garbage'."
- New Media Are Evil: Hoo-Lan feels that triggering the invention of television was like giving a loaded rifle to a child instead of a watergun. At the time, he was trying to slow down humanity's technological progress by "Turning their brains into Swiss cheese". You know, by improving global communications.
- The Nudifier: After being "abducted," Peter has to go through some sort of decontaminating process to get on the New Jersey. He refuses to undress, so the aliens freeze him with a force field and send a laser crisscrossing over his body. The field turns off, Peter moves, and his clothes instantly fall to tatters on the floor, prompting a small Naked Freakout.
- Nice Job Breaking It, Hero: The kids' efforts to thwart Broxholm in the first book actually end up hurting their cause later.
- Noble Profession: Broxholm and Kreeblim describe teachers as the most important job in the world.
- Not Evil, Just Misunderstood: Broxholm and Kreeblim are the antagonists of the first and second book respectively, but both imply that there's something more at play with both characters, and the third one shows that they were trying to save Earth the whole time.
- Not Now, Kiddo: Averted in book 3 — Peter interrupts a meeting of some kind to get CrocDoc back to his office to help Hoo-Lan. Even though he just barged in with a cry of "Your office, now!", CrocDoc doesn't brush him off and instantly follows him. Good thing too.
- Our Ancestors Are Superheroes: In one of the later books, the protagonists learn that all humans were once telepaths. People eventually suppressed this ability because of the growing population — contact with so many other minds would have driven them insane otherwise. This is used to explain, in part, why Humans Are Bastards sometimes, as they evolved to coexist using a means of communication and understanding which they no longer possessed.
- Phlebotinum Analogy: The exact same one that's used in A Wrinkle in Time. Possibly a Shout-Out.
- Planet Spaceship: The New Jersey is slightly smaller than Earth's moon, and has members of more than 10,000 species on board. It's considered impressively small for a mothership class ship.
- Platonic Boy/Girl Heroes: Susan teams up with Peter to work together to expose the alien. Peter makes it clear that She Is Not My Girlfriend at one point in the first book, offending Susan (despite her not having a crush on him either).
- Pokémon Speak: Poot!
- "Rear Window" Investigation: In the first book, Susan breaks into her new teacher's house to look for evidence that he truly is otherworldly. Unfortunately, her lookout had a short attention span. Hilarity Ensues.
- Red Herring: Duncan figures out that one of the four new teachers at his school must be an alien spy. Predictably, the one he's most suspicious of turns out to be innocent.
- Reset Button: Averted in the second and subsequent books. Although Duncan's intelligence boost is temporary (albeit lengthy), it's made clear that when it wears off he won't go back to being the same bully as before, but will instead realize that he has the potential to be so much more than just a bully, and learn from the experience.
- Right for the Wrong Reasons: Susan and Peter are mutually this. Susan believes Broxholm to be the malevolent vanguard of an alien invasion because he brainwashed a teacher into being stricter and is an all around unpleasant person. Peter claims Broxholm is just studying humanity. As evidenced by the fact that he chose to infiltrate an elementary school rather that some high level government facility and is, underneath the jerkass behavior, a pretty competent teacher. Turns out Broxholm IS studying humanity for a coalition of aliens as they debate what do about the threat of humanity's inevitable emergence on the galactic scene, one option of which is to destroy the species (though even the aliens backing this option are presented as finding it abhorrent but necessary).
- Rubber-Forehead Aliens: Most of the main alien characters are like this, especially Broxholm, Kreeblim and Hoo-Lan. Somewhat justified in that the ship has a great variety of aliens from up to 10,000 worlds, and it would make sense to select those most similar to humans as infiltration agents and liaisons. See Starfish Aliens for plenty of aversions.
- Sadist Teacher: Assistant principal Manuel "The Mancatcher" Ketchum and Mr. Black in the second book.
- Secret Message Wink: In the third book, Hoo-Lan is seemingly comatose in sick bay after a psychic incident, but while Peter is visiting him, he briefly opens one eye. The movement immediately strikes Peter as significant, but it's not until half the book later that he realizes Hoo-Lan was winking at him, to signify that the coma was fake.
- Shoe Phone: The aliens pack laser guns that look like ordinary pencils. Other fantastic devices are cunningly (and apparently seamlessly) disguised mundane objects. Mental note: Don't EVER ask Broxholm if you can borrow something to write with.
- Sliding Scale of Idealism Versus Cynicism: The various aliens fall all over this scale.
- To clarify: the more idealistic aliens want to leave the humans alone, or even engage in diplomatic relations with the humans, while the more cynical aliens want to dominate the humans, or just blow them all up and wipe out the human race.
- Snooping Little Kid: What the main characters essentially are in the first two books, in their attempts to get proof that their teacher is an alien.
- Some Call Me "Tim": In the last book, the protagonists meet an alien who fills a whole room. When asking for its name, they find out his name is long and almost unpronounceable, sounding something like "Uhuurbeheegjuli"; Duncan mishears "Big Julie" (sounding like a character from Guys and Dolls) and the name sticks. There is also "CrocDoc" whose real name is Kritzklumpf but Peter calls him this way internally before learning his name.
- Special Person, Normal Name: Broxholm goes by the the nondescript human pseudonym "Mr. Smith." Of course.
- Starfish Aliens: Some of the aliens have rather bizarre anatomies by human standards, especially the New Jersey ship captain who is a bunch of crystals in a jar. Big Julie is an alien literally the size of a house, but who must separate into smaller, ambulatory parts in order to transport himself. Several members of the leadership council are this, including one that appears to be made of shadow and another whose body seems to be composed of "red seaweed."
- Many races are undescribed, but the third book takes pains to emphasize the massive assortment of types of aliens, including something like 30 varieties of bathrooms, repulsive-looking alien foods, and a selection of furniture so vast that it takes many minutes to select a chair (and later, a bed) that would fit a human boy comfortably.
- Starfish Language: The Captain "talks" by making tinkling sounds with his crystal body. Many of the aliens communicate through various non-verbal signs (which the translator microbes do their best to decipher). For example, Broxholm "sighs" by stretching his nose to absurd lengths (and laughs by having his nose twitch), Kreeblim emotes through her "hair", and one large, pickle-like alien makes various exclamations by rearranging his warts and emitting powerful odors. As an inversion, we twice see aliens wink at humans to signal something even though the gesture has no meaning in their own cultures.
- Stay with the Aliens: The first book ends with Peter Thompson deciding to go with Broxholm, since his father's indifferent to his existence and he believes no one will miss him. The next three books more or less deconstruct this decision. Then Susan and Duncan wind up staying with them for good at the end of the series.
- Stern Teacher: Broxholm, as "Mr. Smith".
- But ultimately a positive example, believe it or not. He believes in the value of honesty and integrity, for example, and he has no tolerance for children who behave violently to each other. This is part of the inspiration for the solution the human children eventually come up with to the aliens' problem: if the aliens were willing to send more teachers like Broxholm, maybe the students could be taught to actually do something about all the violence.
- Take a Third Option: Or rather, a fifth. The aliens argue over about four different ways to handle the humans' situation. Either: leave the humans alone and see what happens, invade and dominate the humans by force to save them from themselves (while fixing the world's problems in the process), blockade the solar system to keep their threat contained, or blow the planet to smithereens and kill all the humans so the humans won't make war on the galaxy. The grand finale of the series is when the human children come up with option number 5: "Give us teachers!" According to the children, if students can be taught right by alien teachers, eventually the human race will get over its violent tendencies, and they can join the galactic community peacefully.
- Teacher's Pet: Mike and Stacy from the first book are nice and helpful to most people but are especially eager to help teachers. They (pathetically) act out to try to lose this reputation so that Broxholm won't kidnap one of them as the "best" student in the class. Subsequently, Duncan, who is a shoe-in for "worst" student, tries desperately to start doing favors for teachers for the same reason. And Peter tries desperately to do this as a Plan B; if the kidnapping can't be avoided, he wants to be picked to go.
- Thermal Dissident: A logistical challenge of all the alien species living together on the Mile-Long Ship. Private quarters are customizable, but the common areas are set to a compromise that has some people in parkas, others nearly naked, and humans pretty comfortable.
- Translator Microbes: Most of the aliens and Peter get a translation device transplanted into their brain so they can communicate to each other. It even translates body language.
- Although it doesn't translate the meaning of the body language, or individual linguistic idioms, which can lead to in-universe "Blind Idiot" Translation. Doc Croc at one point uses a phrase that translates to "I hope I never have to eat your children". Um, thanks, I guess?
- Other in-universe Blind Idiot Translations include such gems as "I salute your sinus cavities" and "I put my hand beneath your grandmother's egg." Apparently these make sense to the alien using such body language, but not to the human protagonist or the readers. Which makes sense, given that certain English phrases (e.g. "Hit the hay") would be nonsensical to those unfamiliar with idioms in that language.
- Although it doesn't translate the meaning of the body language, or individual linguistic idioms, which can lead to in-universe "Blind Idiot" Translation. Doc Croc at one point uses a phrase that translates to "I hope I never have to eat your children". Um, thanks, I guess?
- Tyrant Takes the Helm: This is what it seems like to Susan when Mr. Smith/Broxholm kidnaps Ms. Schwartz and replaces her as a boring and strict substitute teacher.
- Villain Protagonist: Duncan becomes this to an extent, since he starts off as The Bully.
- Violence Really Is the Answer: The aliens are generally all high-minded pacifists who abhor violence. However, some of them are willing to destroy the human race if that's what it takes to protect the rest of the universe from us.
- Broxholm is a pacifist to the point where he would rather publicly unmask and fail his mission than harm any of the children attacking him, but during their study of earth he witnesses something (loosely implied to be an imminent rape) that causes him to knock someone out.
- Vitriolic Best Buds: A one-sided example — Duncan's introduction as The Bully to Peter is completely at odds with his claim later that he actually likes him. Susan is baffled, but can't detect anything but sheer sincerity from him. The next book shows Duncan's perspective, making it clearer that he just doesn't know how to express friendship properly.
- We Need to Get Proof: What kicks the plot of the first two books into action.
- What Measure Is a Non-Human?: Inverted. Here it's the aliens who are trying to decide the relative value of human lives.
- Wiki Walk: Peter experiences this when plugged into a virtual reality machine. You can start off on a boat, see a bird in the distance, have it appear in your hand, inhabit its body to see from its POV, and have a million other such experiences. There are strict limits on how long you can use such a device, since it can act as a Lotus-Eater Machine to some beings. If it ever gets hooked up to TV Tropes, the galaxy is probably doomed.
- Wise Beyond Their Years: Duncan becomes this after the aliens expand his mental capacity.
- Would Hit a Girl: During his time as The Bully, Duncan does this to Susan, although it was an accident.