[[folder:Main Students]]
!'''Adam M. Lyon'''
->Voiced by: Creator/NikaFutterman

A human boy who was transferred from Chester Arthur Middle School to Charles Darwin Middle School by an accidental misspelling of his last name from "Lyon" to "Lion".
* AdamAndOrEve: It can be perceived that Adam, being the first human male in an all-animal environment is a biblical reference.
* BerserkButton: After dealing with repeated torture from Jake, Pixiefrog, or CDMS in general, Adam will often lose his mind in the climax or ending of a few episodes.
* BodyHorror: At the end of "Hyena and the Mighty", Adam gets beat up by random machines after threatening Rufus to stop crying and Adam's beating makes Rufus laugh and results in Adam getting injured and bruised. But he deserved it for the massive jerk he was being.
* ButtMonkey: He constantly gets in trouble for Jake's misbehavior, gets hurt a lot, has bad luck, etc.
* TheBore: He became this in "Wild Thing", where his friends, teachers, and even bullies would be driven mad by his long, drawn out tangents about his personal life, internal struggles, backstories, etc.
* CharacterDevelopment: He's not only grown more accustomed to his animal school, but he's embraced it. In late season 3 and season 4, there are also episodes, where he stops playing the straight man and acts just as goofy as Jake and Slips, if the episode were to focus on the problems happening with another character, such as Windsor or Ingrid.
* CharacterizationMarchesOn: However, that didn't stop him from having [[AesopAmnesia Aesop amnesia]] in a few later episodes, with him once again, babbling on and on about how he's the only human and he misses his old school, [[BlahBlahBlah blah blah blah]].
* TheChewToy: Most of his haplessness is played for comedy.
* ChickMagnet: He became this in "I Got Rhythm". Also in "The Frog Principal", but only because of a [[LovePotion love potion]].
* CollectorOfTheStrange: Collects weird [[ShowWithinAShow Captain Clowny]] merchandise and takes it to extremes. He even has a Captain Clowny grandfather clock in his room, which he uses as his regular alarm.
* DeadpanSnarker: Pays to be this if you're the OnlySaneMan of this school.
* DidNotGetTheGirl: Endings to plots with Kerry consistently zig-zag from this, to the opposite.
* FacePalm: Tends to do the forehead slap a lot.
* FailureHero: Most of the time.
* FieryRedhead: ... You could call it that ...
* GoofyPrintUnderwear: Adam has underwear with a picture of Captain Clowny's face in the butt, with a real red nose, that actually honks, when squished.
* TheHero: The closest this show has to one.
* JerkassBall: "The Hyena And The Mighty".
* JumpingOffTheSlipperySlope: "The Hyena And The Mighty"; his abuse of Rufus Hyena. Particularly the scene where he threatens the hyena with physical violence to stop crying.
* KickTheSonOfABitch: See BodyHorror above.
* LoveMakesYouDumb: Adam can do a lot of stupid things, just to impress Kerry.
* MeaningfulName: His first name is a biblical reference. Adam from the bible was the first human man, placed on a planet with it's only other inhabitants being animals. Meanwhile, Adam from the show is the first human boy, sent to a school, with it's only other students being animals.
* TheNapoleon: He's in middle school and is short and stout.
* OnlySaneMan: ''Literally,'' and figuratively.
* RealMenWearPink: He can be rather effeminate at times and has been noted to have a rather girly voice.
* RedHeadsAreUncool: Though, the fact that he's a ginger usually has nothing to do with his loserdom, it is a running gag for people to poke fun at his hair color.
* SensitiveGuyAndManlyMan: Sensitive Guy to Jake's Manly Man.
* StrangerInAStrangeSchool: A human boy accidentally sent to an animal school.
* TokenHuman: The only human of Charles Darwin Middle School.
* WantingIsBetterThanHaving: He had this in one episode when he temporarily went back to his old school, finding Charles Darwin Middle School to be more fun and interesting in comparison.
* YouthfulFreckles: Because he has red hair.

!'''Jacob "Jake" P. Spidermonkey'''
->Voiced by: Creator/TomKenny

A spider monkey who quickly became Adam's best friend. He is often very possessive of Adam and hates not having him around regularly. Jake is emotional and goofy who takes to heart some of Adam's comments and actions, leading to some overly dramatic and exaggerated reactions. He can be lazy and selfish, but at the same time he is also fairly sensible.
* AmbiguouslyGay: Jake appears to like Adam as a bit more than just his best friend. He is shown to be excited when he gets rainbows on his report card, plus he's obsessed with his own butt.
* AnimalStereotypes: Oh look, the monkey character is hyperactive and nutty.
* DirtyCoward: Whenever Adam is even remotely involved in one of his destructive antics, he tries placing all the blame on Adam. Sometimes it works, sometimes [[TakingYouWithMe Adam goes down with him]], but there's never a moment, where Adam doesn't get in trouble.
* CrazyJealousGuy: A rare male-on-male example whenever Adam hangs out with somebody else.
* EverythingsBetterWithMonkeys: A spider monkey.
* IdiotHoudini: Usually when he causes mischief, Adam gets the blame.
* {{Jerkass}}: Not such a good pal to Adam.
** JerkWithAHeartOfGold: He does care about Adam deep down.
* TheLancer: To Adam.
* LargeHam: Like other characters played by Creator/TomKenny.
* NeverMyFault: Never takes responsibility for his actions. Ever. Most of the time, the blame is placed on Adam.
* NiceHat: Got a cool, blue baseball cap.
* PrehensileTail: Well he is a spidermonkey after all.
* RunningGag: His obsession with his own butt.
* SanitySlippage: Jake's mental state is incredibly fragile and can oscillate from calm and friendly to psychotically dangerous at a moment's notice.
* SensitiveGuyAndManlyMan: Manly Man to Adam's Sensitive Guy.
* VerbalTic: Tends to add "Be Somenbody" to the end of sentences, where he tries persuading someone to do something.
* WithFriendsLikeThese: He's willing to throw Adam under the bus whenever Jake does something bad.

!'''Windsor Gorilla'''
->Voiced by: Rick Gomez

A highly intelligent lowland gorilla who serves as the anti-bully at the school and often gives confusing wisdom to people. He speaks in a soft-spoken and nearly monotonous manner, often stringing together technical words as a matter of his normal speech.
* AmbiguouslyBi: In The Hyena And The Mighty, he calls Rufus Hyena his sweet, implying the two may be in a relationship despite Rufus being a one shot character. However, later, he was seen being attracted to another female gorilla.
* TheBigGuy: A large gorilla.
* BlackFace: Lampshaded in "Flesh Fur Fantasy", when Windsor got offended by Adam dressing as a gorilla.
* BrainyBrunette: He is considered "brainy" and his hair does in fact have brown pigments. Fits like a glove.
* ComicallySerious: Sometimes, he can be at his funniest, when he's just explaining something logically.
* DeadpanSnarker: Prone to sarcasm.
* ForScience!: That's Windsor alright.
* GeniusBruiser: He's both intelligent and powerful.
* GentleGiant: Despite his massive physique, he's perfectly capable of taking care of a baby for a school project.
* ParentWithNewParamour: Windsor played the "disapproving kid" role, when Mr. Mandrill started dating his single mother.
* SesquipedalianLoquaciousness: Windsor tends to make his sentences as overly eloquent as possible, by throwing in as much big smart words as could possibly substitute shorter ones.
* ShownTheirWork: Gorillas are known to be large, intelligent and generally mild-mannered. Windsor's status as a [[TheStoic stoic]] GeniusBruiser fits perfectly in this regard.

!'''Ingrid Giraffe'''
->Voiced by: Creator/GreyDeLisle

A female masai giraffe. Her towering height only adds to her feelings of insecurity as she tries desperately to blend into the background. She has a crush on Adam.
* {{Adorkable}}: Shows shades of dorky behavior. She's gawky, gangly and sweet.
* ApologisesALot: She's sort of been programmed to say she's sorry, whenever someone gets mad at her, whether she actually did them wrong or not.
* BreakTheCutie: Quite a few episodes do this to her.
* TheChick
* CuteAndPsycho: Her obsession with Adam causes her to become aggression and dangerously insane at times.
* CuteClumsyGirl: Tends to trip frequently.
* ClingyJealousGirl: She tries to break up Kerry and Adam more than once.
* DoggedNiceGirl: To Adam.
* HugeSchoolgirl: The tallest student in the school (her head is out of the screen most of the time).
* InterspeciesRomance: Her crush on human boy, Adam Lyon.
* LongNeck: Perfect example.
* ShrinkingViolet: A shy gorilla.
* StalkerWithACrush: To Adam of all people.
* {{Yandere}}: She can get pretty crazy about her crush on Adam.

!'''Slips Python'''
->Voiced by: Rick Gomez

An easy-going, street-talking green tree python. He is an underachiever and excessive daydreamer who's gullibility allows him to believe anything he hears, which makes him a constant source of misinformation.
* BewareTheSillyOnes: Despite being a ditzy and a self-admitted "loser flunkie", he's the only member of the group who is an actual carnivore, and can be rather dangerous when he becomes hungry.
* CatchPhrase: Using phrases like "Dude" and "Brother", when talking to anybody.
* CloudCuckooLander: His antics and personality make him border one being one
* TheDitz: Moreso the anyone else in the show. He is very gullible.
* [[DoesNotLikeMen Does Not Like Women]]: Slips is the only member of the pack, who's never had a love interest, girlfriend, etc. He's an independent dude, who just doesn't have the time or effort for chicks.
* DumbIsGood: Seems to be the most laid-back and care-free member of the pack, due to his stupidity and lack of knowledge about anything going on around him.
* DumbassHasAPoint: Slips is actually a distinguished, highly sophisticated young man, whose intelligence is being repressed by Jake and his peer pressuring behavior, as seen in "The Ivy League".
* EnlightenmentSuperpowers: In "Mellow Fellows", he had a deep understanding of human and animal emotions and was able to effortlessly solve people's most internalized of mental and psychological distress in seconds.
* TheHeart: He's the member of the pack with feelings.
* IHaveNoSon: Though it's never seen on screen, Slips heavily implies in dialogue, that his father disapproves of him being such a failure. Fortunately, he seems to [[IgnoranceIsBliss delightfully dim-witted to notice]].
* InvisibleAnatomy: Though it's rarely ever shown, Slips will prove the ability to manipulate his sleeves, despite having no arms.
* NonMammalianHair: His blonde hair
* ReptilesAreAbhorrent: Averted. He's actually a pretty decent guy.
* SeventiesHair: He's got a blond wavy gravy hairdo, which goes great with his hippie-like personality.
* ShownTheirWork: Pythons are slow-moving, nearly silent animals that can often be found hanging from tree branches and sunning themselves, especially after a particularly big meal. Imagining one as a laid-back slacker is not much of a stretch.
* SurferDude: Talks like this.
* TheStoner: Acts like one.

!'''Guadalupe "Lupe" Toucan'''
->Voiced by: Creator/GreyDeLisle

A female Keel-billed toucan, who is loud-mouthed, acerbic, dominating and materialistic, although she considers herself to be mild-tempered and low maintenance.
* BerserkButton: Telling her you don't think she's pretty.
* FunnyForeigner: She'd probably be nothing more than the [[TokenMinority token Hispanic friend]] if cast was all humans.
* GagNose: Or in this case, a beak.
* GenkiGirl: Loud, exuberant, crazy at times.
* HenpeckedHusband: This is how she treats her boyfriend, Corey.
* MotorMouth: Often runs her beak, in conversations with Ingrid or Corey.
* JerkWithAHeartOfGold: Lupe has a good heart despite how annoying she is.
* SecretIdentityVocalShift: In "A Very Special Boy", she reveals that her real voice is perfectly normal and she speaks fluent English. She just disguises it with a loud, raspy, Spanish accent, to ward off predators.
* SmallAnnoyingCreature: She can be this at, her very worst.
* SpicyLatina: She talks with a Latino accent that's super seductive.

[[folder:Other Students]]
!'''Virgil "Bull" Sharkowski'''
->Voiced by: Creator/PhilLaMarr

A bull shark and the school's bully.
* AlwaysSomeoneBetter: His older sister is a way better bully than he'll ever be. He's extremely sensitive about this fact. Especially so when she managed to teach Adam to go frenzy in minutes though trolling. A concept he himself spent the whole episode trying to teach the ever oblivious Adam to no avail.
* BigLittleBrother: His older sister is much smaller he is.
* TheBully: At least until his big sister comes in.
* MobileFishbowl: Wears a special headset over his gills to breathe while on dry land.
* OnlyKnownByTheirNickname: He's mostly called "Bull"
* VerbalTic: Takes a deep breath between his words every once in a while.

!'''Henry Armadillo'''
->Voiced by: Creator/TomKenny

A nine-banded armadillo with a Texas accent and a reporter in the school media.
* FifteenMinutesOfFame: Earned that in "Disregarding Henry".
* Adorkable: Some might see him that way.
* UsefulNotes/AmericanAccents: Southern
* ButtMonkey: If there's anyone at the school, who gets crapped on more than Adam, it's Henry. Unlike Adam, however, he still manages to keep a [[ThrowTheDogABone bright and sunny attitude]] no matter what happens to him.
* CheerfulChild: Even though he's probably the most mistreated, unfortunate soul at Charles Darwin Middle School.
* HarmlessVillain: In "Making the Grade", he turned to the dark side and caused no harm.
* NerdGlasses: Wouldn't be complete without them.
* NiceGuy: He's a kind, loving creature to everyone. And that's the reason, he's the school's biggest target for bullying and abuse.
* TooKinkyToTorture: He seems to ''like'' everyone treating him like crap.

!'''Phineas Porpoise and the Spiffies'''
->Voiced by: Creator/PhilLaMarr

A nerdy bottlenose dolphin and his posse of gifted students.
* TheBully: He's a rare example of a ''nerd'' being one of these, being an InsufferableGenius who lords his intelligence over everyone, especially Adam.
* {{Catchphrase}} : In "Shark Fin Soupy", it was "How Cliche."
* TheDreaded: As noted in one episode, it's not recommended that one barrows from the Spiffies because they tend to ask for favors in return. Likewise, the other students hate the idea of being in a class with them.
* ExtravertedNerd: Doesn't seem to care about being humiliated.
* HollywoodNerd: For an anthropomorphic dolphin, he doesn't look too shabby.
* InsufferableGenius: Phineas has quite the large opinion of his intellect.
* TheLeader: Phineas is this of his fellow nerds: [[ShownTheirWork a pig, an elephant, an octopus, and a parrot]].
* NerdGlasses: The entire gang wears this.
* NonindicativeName: Though Phineas Dolphin doesn't quite have the same roll off the tongue.
* ShownTheirWork: Real bottlenose dolphins are famous for their intelligence and infamous for having many less than amiable behaviors. Hence, Phineas combines those two traits and becomes a nerdy version of TheBully.
* SicklyNeuroticGeek: Talks like this.
* SmartBall: Seems to know pretty much everything. So long as it's about [[BlandNameProduct Prisons and Lizards]], that is.
* SmartPeopleWearGlasses: Gang members of The Spiffies can be identified by their iconic glasses.

!'''Margaret Rhino, Joanna "Joanie" Ox, and [=LeTanya=] Hippo'''
A trio consisting of a Sumatran rhino, cape buffalo, and hippopotamus.
* BigBeautifulWoman: Although, I wouldn't be too sure about the whole "beautiful" part.
* BigEater: All three of them.
* BrainlessBeauty: All of them, but Joanie seems to be the dumbest of the few.
* TheCheerleader: All three of them are on the CDMS Jungle Girls team.
* FatAndProud: I hope to God they are.
* GirlPosse:
** AlphaBitch: LeTanya Hippo
** BetaBitch: Margaret Rhino
** BrainlessBeauty: Joanie Ox
* RhinoRampage: Can happen with Margaret, through LeTanya tends to be the angry one of the group.
* SassyBlackGirl: Latanya. How couldn't she be, when having the unmistakable voice of [[Crator/CreeSummer Cree Summer]]?
* ValleyGirl: Joanna

!'''James Ant'''
A macho red ant, who seems to have no trouble, humiliating himself. He's smallest student at Charles Darwin Middle School.
* CasanovaWannabe: Acts like a real hunky ladies man, but can't get a girlfriend.
* ExtremeDoormat: Allows himself to be literally stepped on and treated as such by just about everyone.
* FarmBoy: He was this in "My Science Project", working on an [[JustForPun Ant Farm]].
* TheFriendNobodyLikes: Doesn't seem to win the affection of his only friend, Henry. Probably because [[AccidentalMisnaming he can't even get his first name right]].
* IJustWantToHaveFriends: Despite his expressive and talkative personality, he comes across as annoying to everyone he meets and has little to no friends. Even his lame, nerdy friends don't like him.
* KidAnova: Although his attempts at winning over the women almost always fall flat.
* NiceGuy: No matter how many times he's crushed or stepped on, he seems to hold no anger toward anyone at the school.
* PetitePride: Seems to have no trouble with being smaller than a bean.
* TheSocialExpert: He's got all the deets on every other student at the school, from their motives, to their personalities, and so on.
* SolarPoweredMagnifyingGlass: Managed to burn himself, by inventing a solar powered tractor for himself, which tragically backfired.
* StrongAnts: Subverts this.
* TinyGuyHugeGirl: This was his short-lived relationship with Sheila Anteater in "Lupe in Love".
* TinySchoolboy: Taken to extremes.

!'''Dickie Sugarjumper'''
->Voiced by: Creator/Tom Kenny

A sugar glider and the school jokester.
* BackstoryHorror: In "That Darn Platypus", his permanent record implied that before coming to CDMS, he actually had a horrifying, past. Mrs. Warthog was terrified by what she saw and urged Principal Pixiefrog [[YouDoNotWantToKnow not to look]].
* {{Catchphrase}}: "Hello, How's Your Trousers?"
* FunnyForeigner: He's the school's funny Australian kid.
* NonindicativeName: Lampshaded in "That Darn Platypus" and "The Ivy League", where Principal Pixiefrog and Mrs. Warthog would discuss the fact that Dickie is actually a sugarglider. There's no such this as a sugarjumper.
* RealMenWearPink: Dickie is the only male cheerleader at the school.
* StockBritishPhrases: Uses quite a few of these.

[[folder:School Staff]]
!'''Principal Poncherello Pegone Pixiefrog'''
->Voiced by: Creator/MauriceLaMarche

The pint-sized African Bullfrog head of Charles Darwin Middle School.
* BunnyEarsLawyer: Although not very bright, he has been shown to handle crisis quite well.
* DeanBitterman: Averted. Though on one occasion he threaten Adam to get Henry to stay in the school[[note]]meaning a nausea-making student would return[[/note]] or else would send him to Siberia, though later he admit he was bluffing.
* PintSizedPowerhouse: He once beat a rhinoceros in a wrestling match.
* TheNapoleon: He's a tiny frog that's in charge of the whole school.
* ReasonableAuthorityFigure: When the entire student body (even Adam) turns on Slips because they don't understand that he's shedding and thought he had a disease, Pixiefrog clears up the misunderstanding by having them watch a documentary on shedding.
* SmallNameBigEgo: And small body.
* WhyDidIthaveToBeSnakes: Well,...lawyers actually. A RunningGag is him trembling or changing his mind when the idea lawsuits are brought up.

!'''Mrs. Geraldine Sharon Warthog'''
->Voiced by: Creator/GreyDeLisle

Principal Pixiefrog's secretary.
* ApatheticTeacher: Or secretary in this case.
* SassySecretary: Responsible for most of the jokes around Pixiefrog.
* OnlySaneMan: At times, in comparison to the other faculty.
* TrademarkFavoriteFood: Chocolate, which she'll devour upon command.

!'''Mr. Cyrus Hornbill'''
->Voiced by: Creator/MauriceLaMarche

A rhinoceros teacher usually seen teaching whatever class is not covered by the other teachers.
* ButtMonkey: Mr. Hornbill has many misfortunes.
* GentleGiant: He's a rhino who's a good guy.
* NonIndicativeName: Hornbills are a group of birds found in Asia, but he's actually a rhinoceros.

!'''Mr. Maurice Mandrill'''
->Voiced by: MauriceLaMarche

The school counselor.
* [[HippieTeacher Hippie Counselor]]: He's the school's psychologist and music teacher..

!'''Miss Chameleon'''
->Voiced by: Nika Futterman

The overly-dramatic drama teacher.
* LargeHam: Her voice can go eerily high.

!'''Coach Tiffany Gills'''
-> Voiced by: Brian Doyle-Murray

A deep-voiced goldfish and the school's gym teacher.
* LargeHam: She almost always talks in a loud voice.
* MobileFishbowl: Teaches from a bowl wheeled around by Vice Coach Horace.
* TheNapoleon: She's a tiny goldfish who is aggressive.
* TertiarySexualCharacteristics: Her eyelashes and bow
* VocalDissonance: You wouldn't expect a goldfish to have such a deep voice, would you?

!'''Vice Coach Horace Ferret'''
->Voiced by: Creator/TomKenny and Robert Goulet in Animal School Musical

Coach Gills' ferret assistant.
* CuteMute: A cute ferret who doesn't speak.
* PerpetualFrowner: Not so smiley.
* SatelliteCharacter: To Coach Gills
* SilentSnarker: His facial expressions convey snark.
* TheVoiceless: Except in Animal School Musical
* WeaselMascot: More like Ferret Mascot.

!'''Mrs. Eugenia Tusk'''
->Voiced by: Creator/CreeSummer

The lunchlady.
* FunnyAccent: Jamaican
* GentleGiant: A tall, kind sort.
* LoveInterest: To Mrs. Hornbill (despite the fact she's married)

!'''Nurse Jacquline Gazelle'''
->Voiced by: Creator/GreyDeLisle

The school nurse.
* DumbBlonde: Played with. She mentioned that she's got a brain the size of a peanut in "Inoculation Day" but, otherwise, doesn't seem to be any dumber than any of the other characters.
* JerkassBall: Tried to shave Rufus's hair off for no reason in "The Hyena And The Mighty".
* TheMedic: Due to being a school nurse.
* SchoolNurse: Duh.

!'''Mr. Blowhole'''
->Voiced by: Creator/DeeBradleyBaker

A whale who is usually seen as the teacher of the nerds. Accompanied by whale noises whenever he talks.

!'''Kerry Anderson'''
->Voiced by: Creator/CreeSummer
* AmbiguouslyBrown: Her [[Creator/CreeSummer voice actor]] is black, making it likely, though compared to other black humans in the show, she looks more Hispanic or Latina.
* {{Love Interest|s}}: She's one of Adam.
* PeekABangs: Her other eye is never seen. So much so, that it turned into a running gag in season 4.

->Voiced by: Creator/TomKenny

!'''The Lyons'''
->Voiced by: N/A
* TheGhost: Adam's parents and other relatives often mentioned but usually never seen.
* TheVoice: Adam's mom was heard in one episode.
*** Adam's grandma's voice was heard, however, we do see her with most of her body out of view (we see her hand pointing).

!'''Mr. I Didn't'''
->Voiced by: Creator/PhilLamarr
* {{Expy}}: Of [[WesternAnimation/SamuraiJack Jack]] voice and appearance wise.

!'''Euripides Sharkowski'''
Bull's older sister.
* BigBrotherBully: Implied, consider Bull hated asking for her help and she seems to be the more dominant of their relationship.
* TheGhost: Was mentioned when Bull barrowed her spare gill phones.
* LadyLooksLikeADude: Although she more sounds than looks like, however, she does, for some particular reason, have a mustache
* LittleBigSister: She's older than Bull, yet he is bigger than she is.
* PinkIsFeminine: She's seen wearing a pink outfit and her "gill phone" (in one episode where Bull barrowed her spare pair) are a hot pink
* TomboyishName: Euripides is a male name
* TomboyPonytail: Her blonde hair is tied in one.
* YourMom: Her insults featured this

!'''Margie Gorilla'''
->Voiced by: N/A
Windsor's Mother
* FlowerInHerHair:According to her cameo appearance.
* TheGhost: Besides a cameo appearance in the background, she's mostly mentioned.
* InterspeciesRomance: Dated a frog, a rhino, and then mandrill
* ParentWithNewParamour: Apparently, she's divorced, as this trope was the subject of one episode where she starts dating Mr. Mandrill and Windsor hating the idea of the former marrying her.
* ReallyGetsAround: Downplayed but she did date Principal Pixiefrog and Mr. Hornbill before getting to Mr. Mandrill.

[[folder:Memorable One-Timers]]
!'''Rick Platypus'''
->Voiced by: Creator/Gilbert Gottfried
An obnoxious platypus who told annoying jokes, and was believed to be an evil alien by everyone else.
* AnnoyingLaugh: Laughs in a loud, raspy, obnoxious voice.
* BrainFood: Constantly made jokes about sucking brain juice.
* EverythingsBetterWithPlatypi: Or worse in this case.
* EvilAllAlong: Though, throughout his appearance, they were doing the [[GoodAllAlong Good All Along]] trope, it was [[DoubleSubverted subverted]] at the very end.
* EvilLaugh: That's probably what the [[AnnoyingLaugh annoying laugh]] secretly was.
* FakingTheDead: Pretended to drown, [[BlackJoke as a joke]].
* StarfishAliens: His true form.
* YouHaveToBelieveMe: The reverse in this episode, where everyone had the crazy belief that Rick was an alien and nobody believed Adam, when he thought he was a normal platypus.

!'''Rufus Hyena'''
Jake's hyena friend, with a real sense of humor, to say the least.
* {{Adorkable}}
* AnnoyingLaugh
* BreakTheCutie: Insulted by Adam, cried several times throughout his episode, terrorized by Nurse Gazelle, threatened by the former at one point
* TheHyena: Literally
* TheVoiceless: Didn't actually speak until the end of the episode, when he was brought back to laughter again.
* {{Keet}}
* MoodSwinger: Went from laughing to crying and back again pretty quickly.
* OcularGushers: Does this when he cries.
* PuppyDogEyes: He's downright ''adorable'' when he pulls it off.

!'''Larry Raccoon'''
A racoon who was expelled from [=CDMS=].
* {{Delinquent}}
* NoodleIncident: How he got expelled isn't quite said but his delinquency had something to do with it.

!'''Possum Girl'''
->Voiced by: Dannah Feinglass
The only other human other than Adam. She pretended to be raised by possums, just to get transferred to Adam's school.
* CuteMute: Though it's all an act, she pulls it off pretty well.
* FanGirl: Has developed some sort of fandom for Adam.
* NoNameGiven: Not even in the credits.
* RaisedByAnimals: That's what her false backstory is.
* StalkerWithACrush: Her deal with Adam.
* YouHaveToBelieveMe: Adam was the only one who knew she could talk and function like a normal human, but nobody believed him.