The Shell is the twentieth episode of Season 3 of The Amazing World of Gumball. It is the ninety-sixth overall.
After accidentally cracking open Penny's shell, Gumball encourages her to show the world who she really is.
At the school play, Gumball and Penny are acting out the final scene. When she mentions kissing him, Gumball freezes. She says that she is improvising, because there was no kissing in the original script. But the play is fast drawing to a close, so he quickly attempts to kiss -- but inadvertently headbutts -- her.
In the dressing room, Gumball is upset over having fumbled on his kiss, and it turns out his headbutting has caused Penny's shell to crack on her eye. She is worried, and Darwin tries to cover her crack up, without success. Reluctantly they all decide to face Mr. Fitzgerald, who is dismayed upon discovering his daughter's crack. Gumball argues that whatever is underneath her shell is nothing to be ashamed of, but Mr. Fitzgerald prohibits him and her from seeing each other again.
At the Wattersons' house, Gumball is too distraught to eat dinner or even discuss his problem with his family. He goes to his bedroom alone to cry, and soon Penny shows up at his window. She announces that her father is considering moving her to another school. Shocked, Gumball protests and encourages Penny to be herself. She takes his advice to heart, and sheds her shell, revealing her true form. Gumball is too stunned to say anything at first, and Penny misinterprets his response as negative, so she shape-shifts into an ugly creature. He tries to explain, but she shape-shifts again and flees his bedroom, before he can declare that she looks "extraordinary."
Gumball goes after Penny, trying to tell her what he really thinks of her, but Penny keeps evading him. Soon, Penny encounters Tobias' parents in their car. After Harold flees, Jackie calls the pest control. Penny continues fleeing from Gumball. On another road, Penny encounters her father in the car (who is surprised and distraught to see her out of her shell). Gumball then goes to Penny and protects her from her father's remarks (that are unintentionally offensive to Penny especially when he remarks that she's become a monster). After Penny shape-shifts to a dragon and flies away, Gumball finally stands up to Mr. Fitzgerald for hurting her feelings. After that, he tells him to "pop the hood" of his car (on which Gumball is on) and Gumball is sent flying to Penny.
He clings onto Penny's leg and struggles to cling on. Penny says that he might get hurt and that he is too heavy. Then Gumball lets go and smashes into Banana Joe's House and Penny lands on the roof of the house. After finding his way through the house, Gumball jumps out of another window and grabs on to Penny's tail. Penny starts flying again, and they fly through a road filled with cars. To stop Penny from hitting a truck, Gumball says that "She is nothing!" to which Penny shape-shifts again from a large dragon to a smaller form. Gumball catches her, and barely avoids the cars on the road.
Once again, Penny starts running off again. Pest control arrives, and the pest controller takes a tranquilizer gun. Just as he is about to shoot Penny, Mr. Fitzgerald rams into his van, making the pest controller miss his shot. Gumball then goes after Penny. The pest controller loads another dart into his gun and fires a second time, but this time he hits Nicole by accident. The rest of the Wattersons (aside from Gumball) arrive with her.
Gumball goes to find Penny in the forest, and he finds her in a wolf form. Penny says to Gumball that she knows he was just trying to protect her. She also grieves her appearance and asks Gumball if he could really love her. Gumball replies with a kiss on the lips, and eventually Penny shape-shifts to her original form. They then gaze at each other affectionately while rest of the Wattersons and Mr. Fitzgerald watch them happily.
- This episode reveals what Penny looks like without her shell. It also marks the last time she is seen with her shell, and the first time she appears without it.
- This was the first episode of Season 3 to be revealed.
- The wig Gumball wears for the play is identical to his hairstyle seen in "The Void" after using hairspray.
- The soap and hair dye in Banana Bob's bathtub has Daniel Lennard's name as the brand.
- Later in the episode, Banana Barbara's painting shows the next scene that comes right after hers.
- Gumball breaks the fourth wall when he asks why Penny and him are always in space when they want to kiss.
- This episode reveals Mr. Fitzgerald's name is Patrick.
- This episode contains the most characters in any episode of the series (46).
- This episode contradicts What Darwin said in "The Sock" as in the episode, Darwin said Gumball will never make the first move. Even though he actually did in this episode
- One of the faces Gumball makes is exactly like the one he made in "The Sweaters" when Penny told Gumball that he was brave to fight Carlton and Troy.
- This is the second time Penny sneaks away from her dad, and goes to the Watterson's house. The first was in "The Knights."
- This is the fifth time that two characters kiss on the lips. The first time was in "The Kiss," the second time was in "Halloween," the third was "The Boombox," and the fourth was in "The Extras."
- This is the first episode in which Gumball and Penny kiss on the lips successfully. It is also the third time they had attempted to kiss, and they were in space when attempting, but the moment was spoiled.
- This is the first episode where the status quo was not restored at the end, as Penny was still shell-less and was dating Gumball in the next episode.
- Ben Bocquelet described the episode as "Miyazaki-esque."
- References are made to some of Hayao Miyazaki's films, such as when Penny morphs into a dragon (similar in form to Haku when he is in his dragon form in Spirited Away), and a wolf, a la Princess Mononoke.
- Gumball kissing Penny who is in another form (specifically her wolf form) could be somewhat similar to Howl's Moving Castle, when Sophie kisses Howl (who is also in another form, specifically his bird form).
- The school play is "Beauty and the Beast," a well known fairy tale written by French novelist Jeanne-Marie Leprince de Beaumont, and published in 1756.
- The logo on the Pest Controller's van resembles the Ghostbusters logo and the van resembles the Cockroach Man's van in Men in Black 1, it could also be a reference from Men in Black 1 that the driver is actually a giant cockroach, where in Men in Black 1, the driver is an alien giant cockroach in disguise.
- Gumball nicknamed Patrick Patman which a reference to Batman or Pacman.
- After the Pest Controller accidently shoots Nicole, Anais and Darwin help her by "beating" him up with her arms. But when they were with Gumball and Penny, The Pest Controller is not seen. It is unknown of what happened to him during that event.