My Teacher Is an Alien

My Teacher Is An Alien is a series of four children novels by Bruce Coville:
 * 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 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 Bastards. 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.

This series features examples of:

 * Alien Among Us
 * Aliens Are Bastards: Zig-zagged, although they are well-meaning and mostly peaceful, they do want to destroy Earth because of their somewhat justified belief that Humans Are Bastards.
 * Alien Lunch: The alien food replicators attempt to create an approximation of Earth cuisine. The "french fry/blueberry pancake" did not work out as well as planned.
 * 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.
 * 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 arch by the series end.
 * Beethoven Was an Alien Spy: Hoo-Lan is revealed to have influenced history throughout centuries, with more or less success. He is feeling especially guilty about being responsible of the invention of television.
 * To elaborate, 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.
 * Berserk Button: Don't ever insult Hoo-Lan in front of Peter. Not even if you're on the galactic ruling council.
 * 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 enhance 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.
 * 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.
 * Cool Teacher: Betty Lou Karpou
 * Crapsack World: The kids (and the readers) take a tour of it.
 * 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.
 * Earthshattering Kaboom: It may come to this.
 * 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.
 * 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.
 * Flowers for Algernon Syndrome: Duncan's intelligence boosting "Brain Frying" is temporary, and he will eventually return to ordinary human intellgence. 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.
 * 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.
 * 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 the kin 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.
 * Getting Crap Past the Radar: It is implied during the torture scene of the fourth book that a woman is about to be raped, pressing Broxholm's Berserk Button and leading the aliens and children to violate the Alien Non-Interference Clause.
 * Gray and Gray Morality: Are humans bastards or was Rousseau right? The books suggest that neither answer is a simple as it seems.
 * 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.
 * Hive Mind:.
 * 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.
 * Humanity on Trial: One of the main plot points of the series in the last two books.
 * Humans Are Bastards: 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 Special: Averted in one respect (See 90% of Your Brain below), 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.
 * 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.
 * 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.
 * Kill All Humans: Some aliens suggest this as the only solution to humanity's violent nature. Hey, at least they feel bad about it.
 * 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.
 * Latex Perfection: The alien teachers typically disguise themselves as humans with this kind of mask, plus gloves and such. Later, even the main human characters wear them. Justified since they have alien technology---for example, its material can change skin tone automatically.
 * 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)
 * Mentor Occupational Hazard: Hoo-Lan.
 * 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.
 * Nice Job Breaking It, Hero: The kids' efforts to thwart Broxholm in the first book actually end up hurting their cause later.
 * 90% of Your Brain: A major concept in the series, humans supposedly would be the most intelligent species in the universe if only we used all of our brains.
 * No Big Deal: Dozens of people see Broxholm unmasked and even more watch his ship escape, but the town's reaction seems to be just pretending en masse that it never happened. There're some hints that the government hushed things up, but it's never fleshed out.
 * Noble Profession: Broxholm and Kreeblim describe teachers as the most important job in the world.
 * Phlebotinum Analogy: The exact same one that's used in A Wrinkle in Time. Possibly a Shout-Out.
 * Plain Name: Broxholm goes by the the nondescript human pseudonym "Mr. Smith" Of course.
 * Pokémon-Speak: Poot!
 * 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.
 * Red Right Hand: An almost literal example: Duncan triggers a fire alarm but a special system (designed to mark pranksters) spurts permanent purple paint on his hand, and he ends up with a bright purple hand.
 * Also Truth in Television.
 * Reptiles Are Abhorrent: Averted. Dr. Kritzlklumpf (aka Doc Croc) is a very gentle and relaxed surgeon who looks like a big red crocodile.
 * Big Julie is implied to be some sort of giant lizard (we never see enough of his body to be sure), and is at first antagonistic. But later on he admits that he is fond of the characters, and never actually causes them any trouble.
 * Reset Button: Averted in the second book. Although Duncan's intelligence boost is temporary, when it wears off he doesn't go back to being the same bully as before, but instead realizes that he has the potential to be so much more than just a bully, and learns from the experience.
 * 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: Sadistic assistant principal Manuel "The Mancatcher" Catchum.
 * 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.
 * 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 "Doc Croc" whose real name is Kritzklumpf but Peter calls him this way internally before learning his name.
 * 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, Kreeblim emotes through her "hair", and one large, pickle-like alien makes various exclamations by 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.
 * Stern Teacher: Broxholm, as "Mr. Smith".
 * 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?
 * 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.
 * 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.
 * 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.
 * 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.