The episode starts with Gumball, Darwin, and Ocho having overslept and rushing off to school. Gumball and Darwin arrive at school to find Ocho beat them, causing Gumball to ask how he got to there before they did. Ocho explains that his Uncle Mario drove him to school which, after some clarification, causes Gumball to deduce that his uncle is the famous Mario and demands that Ocho marries him. After some deliberation, Gumball finally concludes that he wants to be Ocho's best friend. Darwin tries to explain how terrible of an idea it would be to manipulate Ocho, but Gumball refuses to listen. Ocho then reappears to test Gumball's trust, taking him to the school gym for a fight.
In the gym, Ocho gets involved in a fight with Julius, Rotten Cupcake, and Scythe. Gumball is forced to take care of Rotten Cupcake and initially attempts to forge a compromise where he pretends to go down, but the plan fails when Rotten Cupcake instead proceeds to beat up Gumball, giving him a kick in the crotch. However, by accident, Gumball knocks him into an exercise pulley, causing the weights to fall on Rotten Cupcake and mash his face in. Gumball then plays it off as deliberate to impress Ocho.
Later, at the library, Ocho tests Gumball's ability to keep a secret by revealing his real name: Harry Tootmorsel, an Old Flemish name meaning "Hot wind from the south." Gumball tries to withhold laughter, eventually causing his eyeballs to pop out. Gumball then asks if Ocho has any more secrets, so Ocho confesses that he uses his childhood blanket as a gag when he takes people's pets hostage.
In the school hallway, Darwin argues against Gumball lending $100 to appease Ocho. After some arguing, Gumball reveals that he got it off of Richard and Nicole's credit card. Meanwhile, at the store, due to Gumball having removed the card's funds, Richard is unable to spend $1 at the grocery store. Larry tells Richard to sign up for a store credit card scheme, which he does, but the interest scheme puts Richard $121,248 in debt (doubling by the second).
On the way home from school, Gumball is kidnapped and forced to either risk his life or Ocho's - either he jumps off of a ledge to spare Ocho or refuses and spares himself. After a botched attempt at stalling, Gumball eventually jumps, after which it is revealed that the kidnapping was a prank set up by Ocho as another part of his test. Gumball is traumatized but attempts to hide it.
As a final test, Ocho brings Gumball back to the gym and into the 'circle of trust,' presenting him with one last task- Gumball must sacrifice Darwin, giving Gumball a hammer to finish the job. Gumball ultimately hangs up pictures around the school denouncing their friendship as an alternative to presumed murder. Darwin is hurt, but through song, the two acknowledge that the declaration does not mean anything.
Gumball then runs off to play golf with Ocho and Uncle Mario, but upon arriving, is bummed to find that he was not the real Mario that Gumball set out to see. Darwin tries to cheer Gumball up and the two try to figure out how to terminate the relationship. Gumball ultimately settles on song, singing of how terrible their friendship was and of the measures he was willing to take to keep Ocho as far from him as possible (for Gumball's own safety). Afterwards, Ocho apologizes, having realized that he went too far because of his trust issues stemming from having another, more famous uncle in the form of "the blue hedgehog who can run really fast." Darwin tries to stop Gumball from going after Ocho again, but he runs off after Ocho regardless, ending the episode and presumably repeating the cycle.
The crossed photos of Darwin on the posters announcing that him and Gumball are no longer best friends are from the episodes "The Tape" and "The Watch."
The ship scene from the ending of "The Nest" is reused.
Several references to the Mario video game franchise can be found in this episode:
Gumball asks if Ocho's uncle drove him to school in a kart, a reference to Mario Kart, and laughs when Ocho replies that his uncle has a plumbing business as Mario is typically portrayed as a plumber. Gumball then asks if he is scared by ghosts, and if he likes stars, dinosaurs, and princesses, all of which are recurring enemies, items and characters in the franchise.
Gumball says "Yahoo!" and "Let's-a go!" in an accent and intonation similar to Mario's. Additionally, he starts singing a song which resembles the Super Star invincibility theme, then mimics actions and sound effects from a typical level of Mario such as jumping on people's heads, going down a pipe, and sliding down a flag pole.
Uncle Mario wears an outfit that is very similar to Mario's outfit.
Uncle Mario's deadpan declaration of, "Hey, it's me, Mario," is based off of the character's trademark "It's a-me, Mario!"
The episode's title and premise may be a subtle reference to the line "My uncle works for Nintendo," which has been used for decades by people who wanted to spread false information about Nintendo games.
The scene in which Ocho pretends to kidnap Gumball and potentially kill him or Ocho may potentially be a reference to a prank done by YouTube personality, Sam Pepper, in which he did a similar prank with another person tricking the latter's friend into thinking he was going to die after "kidnapping" him.
The posters announcing that Gumball and Darwin are no longer best friends are a reference to a similar Facebook post which quickly turned into an Internet meme.
When Ocho says he has an uncle who is a blue hedgehog and can run very fast, Gumball thinks of Sonic the Hedgehog. The way he runs back to Ocho at the end of the episode is also similar to Sonic's run.
When Gumball got off the bus, he was whistling the Kanto Route 1 theme from Pokémon.
When going down the flagpole, Gumball sings the victory fanfare from Final Fantasy.
[The episode starts with Ocho running on the sidewalk, panting. Gumball and Darwin suddenly walk by him in a hurry as well]
Ocho: You're late too?!
Gumball: Yeah, the alarm clock went back to sleep mode, and I didn't have the heart to wake it up. You?
Ocho: My alarm clock didn't dare wake me up, not after what I did to the last one!
Gumball: [Uneasy] Right, uh, well, see you at school!
[Frightened, Gumball and Darwin increase their speed, leaving Ocho behind]
[The school bell rings. Gumball and Darwin rush past the lockers and are surprised to see that Ocho is already there]
Gumball: [Gasps] How did you get here first?!
Ocho: Yeah, my Uncle Mario gave me a lift.
Gumball: [Tries to hold back a laugh] What, in his go-kart?
Ocho: Nah, he only races at the weekend. During the week, he's too busy with his plumbing business.
Gumball: [Laughs harder, wiping away a tear] Wait, is he scared of ghosts, by any chance?
Gumball: And he likes stars, dinosaurs, and princesses?
Ocho: [Nods] Mm.
Gumball: And he's your uncle?
Ocho: Yeah. So?
Gumball: [Inhales deeply; Grabs Ocho] Marry me!
[Teri and Masami pass by on the other side of the hall, hinting at a bet they made regarding Gumball]
Teri: Called it.
Masami: Guess I owe you twenty bucks.
Gumball: No, okay, I get it. I'm moving too fast. I meant adopt me.
Gumball: Date! Uh, should we d-date first?
Ocho: [Confused] You mean you want to be friends?
Gumball: Best friends!
Ocho: Uh, okay...
[Ocho hovers away, and the camera zooms in on Gumball]
Gumball: [Smiles broadly; Hushed] The rest will follow naturally.
Darwin: Gumball, it's a bad idea to manipulate someone's feelings for your own gain. Especially if that someone's Ocho.
Gumball: Yeah, I get your point, but on the other hand... Mario!
Darwin: Let's just take a moment to remember what Ocho's like when he's angry.
[Gumball and Darwin start to ponder; In their imagination, Tobias is walking down the school hallway when he accidentally bumps into Ocho. Suspenseful music starts to play as they lock eyes. Tobias runs around a corner and hits a dead end, then turns toward Ocho, who is silently inching closer. Their faces are almost touching when the vision ends]
Gumball: Eh, he's not that bad if you think about it with different music.
[Gumball and Darwin re-imagine the same scenario, but with the gentle strumming of an acoustic guitar]
Darwin: You'll regret this.
Gumball: Yeah, but my tombstone will say, [Quietly] "This dude met Mario."
Ocho: Follow me! I need to test you before you can enter my circle of trust.
Gumball: Okay, where do we start?
Ocho: I need to see if you've got my back in a fight.
[Gumball starts getting nervous and exchanges glances with Darwin, who is smirking back at him. Ocho is already in an altercation with Julius, Rotten Cupcake, and Rat, by the time Gumball timidly strolls into the gym]
Julius: I'm gonna punch you so hard, you're gonna beg for your baby teeth back!
Ocho: Yeah? Well, I'm gonna punch you so hard, it'll make the Big Bang seem like the Little Pop!
Gumball: How did this situation escalate so quickly? I was literally two steps behind you!
Julius: [Groans] Get them!
[Ocho dodges a punch from Julius and knocks him down with a blow from above. Rat jumps at him next, but is easily swatted away. Meanwhile, Gumball is cowering with his arms shielding his face. Rotten Cupcake approaches him and growls]
Gumball: [Scheming] Okay, don't worry, I'm not gonna hurt you. I'm just gonna take a swing, and you just go, "Aah!" and take a fall and we're good, all right?
[Rotten Cupcake kicks Gumball in the groin, and he drops to the floor in pain]
Gumball: [High-pitched] Okay, great. You're right. It looks better if you put up more of a fight. [Stands back up] So next, I--
[He continues to beat up Gumball by slamming a trashcan over his head, repeatedly striking its side with a broom handle]
Gumball: So now I'm gonna pretend to kick. You dodge, and then pretend to fall on a right hook.
[Still wearing the trashcan, Gumball moves forward while kicking and punching the air, taking Rotten Cupcake by surprise]
Rotten Cupcake: What?
[Rotten Cupcake backs away and trips over the broom. Falling against the bench of a lat pulldown machine, he briefly pulls on the handlebar, causing the connected weights to rise. They come crashing down directly on top of him, after which Gumball removes the trashcan. His face bruised and swollen, he watches what remains of Rotten Cupcake stagger toward him and collapse]
Gumball: [Notices Ocho behind him] Uh, yeah! That-That's what you get!
Ocho: Very good, but we're not done yet.
Gumball: [Whispers to Rotten Cupcake] Good job. You really sold it.
Rotten Cupcake: [Severely injured; Struggles to speak] Please call an ambulance.
Gumball: Okay, now you're just being hammy. [Walks away]
[Gumball and Ocho are in the library, sitting on opposite sides of a table]
Ocho: Now I need to test if you keep a secret. Ocho isn't my real name. [Writes on a piece of paper; Slides it to Gumball]This is my real name.
Gumball: Harry Tootmorsel. [Stifles a laugh]
Ocho: [Irked] But real friends don't laugh at each other's misfortune.
Gumball: [Exhales slowly, straining to maintain his composure] Of course, Tootmorsel... Is it Nordic?
Ocho: Old Flemish, actually. It means "the hot wind from the south." It's a family name that's been passed down the generations. My grandfather passed it. My father passed it. One day, I will pass it.
[Gumball continues to withhold his laughter, resulting in his head swelling and turning red. His eyeballs pop from their sockets, and he pulls them back in, returning to normal]
Gumball: Cool secret. Anything else?
Ocho: [Embarrassed] I still sleep with the blanket I had as a baby.
Ocho: [Stern] I use it as a gag when I take people's pets hostage.
[Gumball waits for him to finish, but is met with awkward silence]
Gumball: Uh-huh. [Pauses again] There's no punch line 'cause it's not a joke, is it? [Whimpers]
[The bell rings. Gumball reunites with Darwin by the lockers]
Darwin: [Angry] Why did you agree to lend Ocho a hundred dollars?!
Gumball: [Hesitant] Because it was another one of his tests.
Darwin: That's not a valid reason.
Gumball: [Scoffs, and rolls his eyes] Because... Mario.
Darwin: That's even worse! Anyway, where'd you get the money from? Even mom and dad don't have a hundred dollars.
Gumball: [Pulls the bill from his pocket] Not anymore they don't.
[Ocho comes on-screen briefly, and snatches the money. Darwin shakes his head in disapproval]
Gumball: But, that's what credit cards are for, right? What's the worst that could happen?
[Scene cuts to Elmore Shopping; Richard is at the checkout counter with Larry]
Larry: So one-hundred expired doughnuts comes to... one dollar.
Richard: Bargain! [Takes out his wallet] Oh, better put it on the credit card.
Larry: [Swipes the card; The register buzzes] The card's been declined, sir.
Larry: I'm afraid I'm gonna have to cut it up. [Snips it in half with scissors]
Richard: [Groans] Ohh, this couldn't get any worse.
Larry: But, we have our own store credit-card scheme that lets you borrow as much as you like. With interest, of course.
Richard: Fine! [Signs the application]
Larry Thank you. [Swipes the new card] According to our interest scheme, you now owe us seventy-five hundred and seventy-eight dollars.
Richard: [Upset] This really couldn't get any worse.
Larry: Unfortunately, the interest rate doubles every second, so you now owe us fifteen-thousand one-hundred and fifty-six dollars.
Richard: [Drops to his knees] It really, really couldn't get any worse. [Cries into his hands]
Larry: Thirty-thousand three-hundred and twelve dollars, sixty-thousand six-hundred and twenty-four dollars--
Richard: Touché, universe. Touché.
Larry: One-hundred and twenty-one thousand two-hundred and forty-eight dollars.
[After school, Gumball gets off the bus and walks along the sidewalk while whistling. A sack is placed on his head, and he finds himself trapped in a speeding vehicle]
Gumball: [Panicking] Gah! Aah! What is this?! What is going on?!
Masked Voice: You took my best friend from me!
Gumball: Who are you?! What do you want?!
[The vehicle comes to stop]
Masked Voice: You took Ocho from me! Now you're gonna have to make a choice.
Gumball: [Terrified] What?! What do you mean?!
[The bag still over his head, Gumball is brought to what appears to be the edge of a building]
Masked Voice: Choose between yourself and Ocho. One of you has to go. Option A: Jump, and I spare him. Option B: Don't jump, and he goes down. So what's your answer?
Masked Voice: "Yes" what?!
Gumball: [Mumbles indistinctly]
Masked Voice: What?!
Gumball: [Keeps mumbling]
Masked Voice: Hold on, let me get closer. I can't hear a word of what you're saying.
Gumball: Ha! You fell into my trap! [Punches empty air]
Masked Voice: I'm on the other side.
Masked Voice: Fine. You've made your choice.
Masked Voice: Make your decision! It's him or you! You're running out of time! Choose, NOW!
[Gumball jumps from the ledge and screams, but only falls several feet]
Masked Voice: Good choice.
[Gumball removes the sack, discovering that the whole thing was a setup done by Ocho at an outdoor skatepark]
Ocho: [Into a megaphone] A true friend always puts the other before himself. [Lowers the apparatus] Also, funny prank, right?
[Gumball sweats, his face twitching, as he experiences traumatizing flashbacks]
Gumball: [Weakly] Yeah. You really got me there. [Whimpers]
The Circle of Trust
[Gumball and Ocho return to the school gymnasium. The room is dark, save for the glow of numerous candles arranged in a large ring. The two of them step into the center]
Gumball: [Nervous] Um, what's this?
Ocho: The circle of trust. To complete the ritual, you must forsake all other friends and declare your loyalty to me alone.
Gumball: What do you mean?
Ocho: [Drops a hammer by Gumball's feet] You must sacrifice Darwin.
[Gumball looks horrified, and suspenseful music plays. In the hallway, he creeps up behind Darwin with the hammer ready to strike, but uses it instead to nail up a picture of him and Ocho. Darwin is displeased as he reads the caption]
Darwin: "Darwin is no longer my best friend. Best friendship is begun with Ocho?" Uh, ouch.
Gumball: Trust me. It's way better than what he suggested I use this for. And this was the final hoop I had to jump through to be friends with that nut case. [Taps Darwin's arm affectionately] You know you'll always be my bae...
Darwin: [Singing] And you'll always be my boo.
Gumball and Darwin: [Harmonizing together] Your friendship gets me through the trials of the day, and through the darkness of the evening too.
Darwin: All right, then, so when do you get to see Mario?
Gumball: Apparently, he's taking me and Ocho for golf! I mean, that's probably the most boring game you can play with Mario, but still. Yahoo!
[The school bell rings. Gumball leaps straight up, his appearance becoming pixelated]
Gumball: Let's a go!
[Gumball runs though Elmore while pretending to be in a video game, providing the music and sound effects a cappella. Jumping on Crocodile Woman, he takes her hat and kicks it at William. It knocks his wings off, which Gumball uses to hop over a barricade. He enters an open manhole, then exits another, covered in filth]
Gumball: Da-bop-a-doo gross. [Resumes vocalizing]
[Gumball jumps along the sidewalk in front of some shops, squashing Susan Benson and bashing his head on several hanging signs]
Gumball: Budda-ba shouldn't have done that. [Bounces from a trash bag to a bin, and then over a fence] Wah, ha, wahoo!
[He grabs the top of a flagpole and slides down, arriving at the miniature golf course. His appearance returns to normal]
Gumball: [Panting; Excited] Hey, man!
Ocho: Oh, hey, dude. This is my uncle.
[An obese humanoid wearing a red shirt and blue overalls turns around, but he is not quite what Gumball was expecting]
Mario: Hey, it's me, Mario.
Gumball: Uh. [Frowns, his hopes dashed]
This Friendship is Over!
[The scene changes to the Wattersons' house. Gumball is in the bathroom, using a toothbrush to scrub his eyes]
Darwin: You must be really disappointed it wasn't the real Mario. Still, makes sense. I mean, any guy would like go-karting, stars, and princesses.
Gumball: I think I'm more upset about the amount of butt he flashed every time he picked up the ball. [Spits from his eyelids] It looked like a huge purple apricot stuffed into a cheap pair of polyester pants.
[The brothers enter their bedroom]
Darwin: So what now?
Gumball: I refuse to hang out with a kid whose own parents have to lock their bedroom door to feel safe at night. [Scribbles on a notepad]
Darwin: Uh, how do you let someone that dangerous down?
Gumball: Off the edge of a cliff.
Darwin: You mean that metaphorically, right?
Gumball: [Erasing what he wrote] Yeah, o-of course.
Darwin: How are you gonna break it to him?
Gumball: A strongly worded letter!
[Darwin glares at him]
Gumball: A mildly worded poem?
[He shakes his head. Gumball sighs, and slow music starts playing in the background. As Gumball sings the ballad, various clips depicting Ocho's volatility are shown]
Gumball: I wanna say you're a real good guy
But we both know that would be a lie
It's been a nightmare being your friend
So it's time for this charade to end
I can't say goodbye
Cause you might grind me down into meat pie
I'll tell the school that you've got avian flu
So it'll be their job to get rid of you
I hope they put you into quarantine
Or lock you up until you turn eighteen
So maybe then I'll never have to fear
That you might suddenly bite off my ear
Please don't bite off my ear
I can't say goodbye
My face will be too mangled to identify
If I could get your house repossessed
You'll be forced to relocate to your gran's in the Northwest
I could get you arrested for stealing a car
I could get you a job as a miner
I could ship you in a crate to Qatar
Or sell you as kebab to a dirty diner
It's not real meat, anyway
I could get your folks to forget you on the freeway
Sell you to a freak show on its way to Uruguay
I could get you stuck on a fairground ride, forever
Send you to a wedding in Somewhere-stan with you as the bride
I can't say goodbye
But it's no use trying to deny
That I don't wanna be friends with you
So do whatever you have to do
[The song ends; Ocho and Gumball are in the schoolyard]
Ocho: [Sighs] I get it. Too intense, right?
Gumball: If I had to rate my stress on a scale of one to ten, I'd score a--
[Gumball lifts his hand to the sky. It stretches all the way up to a passing airplane, bursting through the fuselage and causing the passengers to scream]
Ocho: [Remorseful] I'm sorry. I shouldn't have tested you like that. It's just, I got trust issues. I always wonder if people really want to be friends with me, or, you know, because of my uncle being so famous and stuff.
Gumball: What? Mario?
Ocho: No, the other one. [Whispers] The blue hedgehog who can run very fast.
[Gumball is speechless]
Ocho: But it's cool. After all we've been through. I think I'm more able to trust people now, so thanks for that. [Floats away as Darwin walks by]
Darwin: Not worth it.
Gumball: [Groans] You're right.
[Gumball follows Darwin off-screen, but immediately changes his mind, racing after Ocho at supersonic speed]