The Doppelgänger is an episode of Season 3 of the The Amazing World of Gumball.
Sticky discovers his feelings for Teri while Gumball and Darwin are on a hunt for someone.
The episode starts with the students at the schoolyard avoiding a ball smeared with poop. The ball bounces around until it is thrown out of the yard and unto Mrs. Robinson's wig (who was with Mr. Robinson in their car passing by). Tobias reveals a spare ball, but the ball refuses to play with them and hitches a ride with a construction worker driving a truck passing by. With no ball, the students separate with Matt, Walter, Lewis and Ronald joining together.
The four realize that Sticky is not with them, and eventually they find him standing there. They are interrupted by Teri's scream. Teri (who had fainted at the sight of the filthy ball) finds some spots of dirt on her feet. She quickly goes to the infirmary. Meanwhile, Sticky is as still as a wall and is immobile. With some effort, the four attempt to make him move. In the end they bring him to the infirmary as well.
In a hallway, Gumball and Darwin hide in the lockers. They are waiting for someone. Darwin pops out of his locker but Gumball tells him to keep hiding and that it wont be long until the person they find arrives.
At the infirmary, the four with a still immobile Sticky arrive. They encounter Teri arguing to the School Nurse. In the end of the argument, Teri goes to the hospital and Sticky is taken in. He eventually recovers and reveals that he is in love. The four are surprised, and Sticky tells them that the person he is in love with is Teri.
Meanwhile, Darwin gets sick of hiding in a locker and proposes a plan B to Gumball. Gumball asks what it is and Darwin replies "Something other than staying in a very cramped space for possibly hours and waiting for someone in one place who might not show up after all and in the end likely wasting our time?". Gumball accepts this but is stuck. As Darwin is about to get out from his locker to free him, Banana Joe locks the locker (as it turns out to be his) entrapping the Watterons.
At lunch, Gumball and Darwin are freed by Rocky (taking the in-between school session to do so). They move on to "Plan B" which involves hiding up a tree in the schoolyard and spying on the students.
In the yard, Sticky is finally normal. However, when Lewis proposes to play soccer, Sticky excuses himself. Lewis discovers that in actuality Sticky was planning to ask Teri out. Sticky then admits it was almost too obvious and tells what he likes about Teri, unintentionally making the scene too cheesy. It turns out to be Tina playing jump rope and Hector eating a cheese sandwich. The four express their support for Sticky, and Sticky is excused from the game.
Sticky goes to Teri and they talk for a little while. Matt, Lewis, Walter and Ronald start to play soccer. However, when Matt asks for the ball, Ronald kicks it clumsily and with much force that it hits Matt's face and bounces upward. The ball hits Sticky, prompting him to fall into Teri's arms. The two embrace awkwardly, but Teri says its okay.
Back to the four. Matt is still awake but is knocked out of his senses. However, when Sticky comes back, too embarrassed to keep talking to Teri, he recovers instantly and demands to know what had happened. Sticky tells them about their hug which encourages Matt to egg Sticky to ask Teri out.
Sticky goes back to Teri but before he can ask her out, she seemingly disappears. Meanwhile, Gumball continues spying until a ball hits his face, stopping him from spying. Teri reappears but disappears when Sticky gives her roses and chocolates. The four (who went to check up on him) encourage him to not give up.
Gumball and Darwin execute a "Plan C" for their hunt of the person they are looking for. They are inside the school, in the hallway watching everyone in their business. Gumball reveals that they are looking for Clayton, and are looking for someone who they think could be Clayton in disguise. They first suspect Banana Joe who they bring into a corner. Eventually they are convinced by Banana Joe that he is not Clayton and when he gives them a tip that Clayton was last seen in the infirmary. The Wattersons free the banana and continue their search.
Back in the schoolyard, Lewis' soccer ball falls in the garbage bin as its owner despairs the ball's dirtiness. Sticky comes back, exasperated after Teri keeps disappearing from him. Matt continues to tell him to never give up.
Alan is interrogated by Gumball and Darwin. After they are convinced that Alan is not Clayton in disguise, they let him go and ask Tobias. To prove that he is indeed himself, Tobias attempts to lift two concrete blocks (also to impress the ladies). When Tobias fails and the blocks pin him down, Gumball and Darwin are convinced that he's the real one and take him off their list of suspects.
Sticky once again attempts to ask Teri out. He finds Teri hiding in the school's side from the Wattersons for an unknown reason but he does not notice this. Surprised by Sticky's sudden appearance, Teri punches him out of the schoolyard and into the road where he is run over. Being 2-dimensional he is carried by the wind unscathed into a trash bin. The trash bin's smell knocks him out. "Teri" meanwhile just shrugs and morphs into Sticky.
Eventually Gumball and Darwin start interrogating Matt, Lewis, Ronald and Walter. "Sticky" arrives just as they ask for Clayton (or if one of them might be him). Matt denies this of course. During their "interrogation", they are interrupted by Teri chasing and spraying another Sticky with orange scented disinfectant around the yard. The Wattersons and the five notice that there are two Stickys.
Gumball immediately suspects Sticky number two (the Sticky Teri had chased). However, when Sticky number 2 (who was unconscious as he was allergic to oranges or just their scents) is proved by his friends as authentic, they all immediately suspect Teri since she states that she was not present from lunchtime and just arrived minutes ago. They first think that she is lying since everyone saw her. They realize that the Teri during lunchtime (and the one Sticky was asking out all along) was Clayton in disguise.
Teri's absence is further proven by a medical receipt from the hospital and by Matt, Lewis, Ronald and Walter witnessing her leaving the infirmary going to there. Teri also points out that there are two of the same person, one of whom can only be one. Feeling dumb for suspecting her, Lewis points to Sticky number one (the first one who had appeared during their interrogation) and everyone starts suspecting him since he is the only suspect left. However, during Teri's interrogation, the fake Sticky sneaks away and by the time they suspect him he is gone.
Suddenly they notice the girls nearby and their table flip over, causing a commotion. Lewis spots Clayton recovering and quickly morphing into Sarah . The Wattersons and the four (Sticky still being unconscious) arrive at the scene. Sarah (A.K.A Clayton) attempts to blend in with the girls and the chaos that he created but Masami unintentionally roots him out, stating that the real Sarah is with Carmen and Penny in cheerleading practice. Clayton finally surrenders to Gumball and Darwin.
Gumball, Darwin and Clayton start chatting and arguing. However Gumball makes their argument too soft to be heard as it turns out to be something secret much to the curiosity of the four and the other girls and the annoyance of Masami. The argument ends with Clayton still being friends with the Watterons and bouncing away happy. When the four demand to know what they were talking about, Gumball and Darwin say that its a secret. Teri rejoins the girls.
After school, Sticky talks to Matt and says that he plans to avoid Teri if it makes her happy. Uninformed (since he was unconscious most of the time and remained untold) he thinks that Teri doesn't like him since she (or in reality Clayton) punched him and kept avoiding him when he tried to ask her out and later (this time the real Teri) sprayed him with orange disinfectant to the point of passing out. In actuality, the real Teri was spraying him since he was dirty from the trash he fell into after he was punched by fake Teri.
Matt asks Ronald if they'll ever tell Sticky about the truth. Ronald says that he didn't tell him since it might disappoint Sticky that his efforts went into asking Clayton as fake Teri out instead. Ronald also adds that he might tell Sticky about it in around 10 years.
• This episode reveals that Teri is Sticky's love interest.
• Once again, the basketball and BLT poster becoming alive reference the episode "The World".
• Lewis makes a reference to Pokémon when he throws the wrapper at Sticky and pretends to summon "Stickachu" with his imagination.
• The scene where Lewis asks "Where's Teri?" then Teri appearing, looking around then putting on a small brown hat is a parody of Perry the Platypus from Phineas and Ferb.
• This episode reveals Sticky's allergy to oranges and their scents.
• Clayton morphs into other people, just like he did from "The Skull".
• This episode has 9 major characters, more than the usual.
• Banana Joe whistles the same tune he whistled in "The Banana" as he is walking in the hallway.
• In this episode, Clayton morphs into three people.
• This episode was originally titled "The Ache".
• Mr. Kreese from "The Sweaters" makes a cameo in this episode.