"The Butterfly" is the twenty-seventh episode of Season 3 of The Amazing World of Gumball and the 103rd episode overall.
During Miss Simian's class, Darwin is inspecting something with his microscope. After he learns that he was inspecting Banana Joe's butt up close all along, he sees everything with butts on them, panicking that everything is ruined (except for Miss Simian's face, which he says looks better). Miss Simian asks them to pay attention to a chrysalis in a jar on her desk, explaining the life cycle of a caterpillar. She promptly sends Banana Joe to Mr. Small's office when Banana Joe flaps his peel "inappropriately" like a butterfly.
When Penny asks if the butterfly can be released after emerging, Miss Simian objects, and tells everyone about the butterfly effect. She demonstrates something like it by causing destructive events in the classroom that ends with a window hitting Tobias's head. Just before she asks them to witness the butterfly's emergence, the class bell rings and she drops her lesson.
Just as Miss Simian and the others leave, Gumball and Darwin see the chrysalis moving and panic. After Gumball takes a hot shower and they both breathe rapidly, the butterfly emerges. The brothers are thrilled by it, and decide to let it free.
At their break time, two construction men have some coffee. When they toast, their mugs break due to their powerful bodies. When the butterfly from earlier lands on one of their heads, the other tries to smack it off but instead punches his friend to a wall. The two men start unintentionally beating each other, all the while apologizing until one loses his arms, and the other has his head sent up to the sky towards a plane. The head says hi to a friend before falling back down.
The next scene shows Mr. Robinson driving his car. While on the road, he drives slowly and sings much to the annoyance of the workers driving to work behind him. Mr. Robinson doesn't care, saying he has all the time in the world and that he's retired. Then he starts taunting citizens (like Larry, by taking his parking space, and the Hobo, by tricking him into hitting a pole). In the latter the Hobo shouts after Mr. Robinson, wishing that he would get what he deserved. The construction man's head then hits Mr. Robinson, and knocks him out. As the Hobo steals 20 dollars from Mr. Robinson's wallet, a wheel from the latter's wrecked car knocks the Hobo unconscious. The 20 dollars flies away with the wind.
Many citizens in Elmore notice the flying bill, and compete with each other for it. The money lands near Marvin, who tries to reach it. But his fragile body prevents him from doing so, and Marvin repeatedly prevents himself from falling down with his cane. The Doughnut Sheriff shows up, and fines Marvin 20 dollars for street dancing without a license. When the officer tries to take the bill he rolls down the street and hits a pole, sending one of his shoes flying.
Nearby, the old lizard woman feeds the pigeons, then feeds on one of them. When Rocky passes by with a bagel, the shoe hits him and makes him inadvertently lean to the lady with the bagel held as if it were a wedding ring. The old lizard woman sees this and accepts Rocky, thinking he was proposing marriage. After the old woman explains her sacrifices for the "moment," Rocky says he "changed his mind" and tries to disappear. He ends up hurting himself, and the old lady calls the Elmore help desk.
At the Elmore help desk office, Karen receives the old lizard woman's call saying she was abandoned by her fiancee. As they sing/talk, Rocky also calls Karen saying that a crazy lady alligator wants to be his bride. Marvin also calls, and says that he (still being stuck with the 20 dollars) will need help standing straight. Mr. Robinson also calls, shouting that he wants to sue whoever made him wreck his car. Karen gets angry with his attitude, and the construction man's head calls too. After they make her angry with all their issues, Karen hangs up on all of them, and throws her desk out of her office.
The desk causes cars to crash into each other, and people to topple over. The people create a domino effect which ends when Hector falls on Sussie's dad. He sneezes, and this causes Charlie to be blown into a roundabout. Rosie nearby panics when the roundabout spins so rapidly that a small tornado materializes. But she calms down when the tornado disappears, and Charlie is launched into the sky. He lands in the Watterson's TV while the weather news is on, causing a tornado to form and Richard to be sucked in it.
Back at Elmore Junior High, Miss Simian returns from her break. She is shocked when she sees that the butterfly is gone. Gumball and Darwin freely admit that they were the ones who did the "decent thing," and released the butterfly. Miss Simian gets frightened, and takes cover. The butterfly comes back, and Gumball wonders how something so tiny could destroy a whole town. He gets his answer when the butterfly flies away from his view, and reveals a tornado that heads towards them.
- Miss Simian
- Mr. Small (mentioned)
- Banana Joe
- Sea Serpent
- Construction Mens
- Orange Woman
- Hexagon Lady
- Gaylord Robinson
- Shape People
- Black Rectangle
- Clipboard Man
- Dr. Butt
- Neck Beard
- The Hobo
- Carmen's father
- Sphere Citizens
- Margaret Robinson
- Spraypaint Can
- Banana Bob
- Jolly Hamburger
- Marvin Finklehimer
- Doughnut Sheriff
- Crocodile Woman
- Rocky Robinson
- Manly Warrior
- Harold Wilson
- Mr. Pepperoni
- Jackie Wilson
- Elderly Chalkboard Woman
- Plaid Old Man
- Shooting Star
- Oval Family
- Cupcake Woman
- Exercise Bacon
- Melted Cheese Guy
- Green Security Guard
- Green Bear
- Patrick Fitzgerald
- Mrs. Fitzgerald
- Football Players
- Sussie's father
- Hot Dog Guy
- This is the first episode to air in 2015.
- This episode aired on the same day as "The Question."
- 65 characters appear in this episode, the most in the entire series.
- Gumball and Darwin are only present during the beginning and ending of the episode, making this their 3rd minor role.
- For the first time in the series, Hector's face is revealed.
- Joe's first name is revealed to be Joseph when Miss Simian calls him.
- This is the fifth time that Elmore is or almost destroyed. The first four were in "The Microwave," "The Colossus," "The Finale," and "The Pizza."
- This is the eleventh time Gumball has changed colors. The first ten were in "The Responsible," "The Ghost," "The Party," "The Flower," "Halloween," "The Game," "The Plan," "The Password," "The Procrastinators," and "The Mirror."
- This is the seventh time Mr. Robinson's car has been damaged. The first six were in "The Debt," "The End," "The Goons," "The Car,", "The Tag", and "The Allergy".
- Music from "The Fan" and "The Party" is reused.
- The Butterfly effect is a real principle in chaos theory, the classic example of which theorizes that a butterfly flapping its wings can alter the path of a tornado or even cause one through a domino effect. This theory was made popular by the film named after it.
- The construction worker losing his arms and remarking that it was "only a flesh wound" is a reference to the Black Knight from Monty Python and the Holy Grail.
- Marvin is seen standing at the corner of the block throughout most of the episode. However, he later appears in the mall.
- A similiar incident happens with Harold; he is seen about to board a bus but is seen not too long after in a line outside the mall. Also the Orange Woman is seen on the plane. Later she is seen fighting for a 20 dollar bill.
- The sign at the "Emergency Call Centre" uses the British spelling of the word "center," even though Elmore is an American town.
- Although five people called Karen, only three telephones are picked up. However, this error eventually corrects itself.
- When Charlie crashes into The Wattersons' house, the mailbox and several flowers are missing from the front lawn.
- When Richard is on the couch and gets swept up in the wind, his eyebrows and eyelashes disappear.