"Pick an Ed" is the 11th episode of Season 5 and the 113th episode of Ed, Edd n Eddy. In this episode, Eddy finds out that someone has called him a no-neck chump through graffiti. Eddy goes undercover as a new kid to find out who wrote the insult. When he finds out people are accepting him and actually thinking that he is cool, he decides to remain as his alter-ego forever.
Class is going on as usual inside a classroom at Peach Creek Jr. High when an explosion comes and the kids trot out, blackened and singed. Among the leaving pupils are the Eds. Eddy is naturally being lectured by Edd, this time for destroying the classroom, but Eddy is in no mood to listen to Edd, instead preferring to joke about how the teacher and Edd looked. Ed then interrupts and mentions how he looked, and says that Chumpy (meaning Eddy) knows funny. Ed and Eddy share a laugh right up until Eddy realizes what Ed called him and demands an explanation.
Without further ado, Ed drags Eddy back upstairs and shows him some graffiti scrawled by the water fountain reading "Eddy is a no-neck chump." Eddy's infuriated at the thought of this, sure that someone's out to ruin his good name, but Edd merely tells his paranoid friend that there's no smear campaign since he doesn't have a good name to ruin anyway.
Besides, Edd has a job to do, sorting lost items for the school lost-and-found, and he's happily doing this work when Eddy bursts in and starts rummaging haphazardly through the clothes. Edd complains that the world has gone mad, but is interrupted by Ed, who is in his happy place. Eddy, still looking through the clothes, outlines his plan for Edd. It seems that he wishes to go undercover, find out who wrote the graffiti and then...well, he'll do something. He then shoves his friends out of the room while he continues the hunt.
When Eddy exits the room, he's wearing new clothes and has disguised his face slightly, but he's still pretty much the same old Eddy. Edd points this out, but his logic is rebuffed by Ed, who's certainly stupid enough to fall for this paper-thin disguise. Eddy then exits the scene to try out his new persona, whom he has dubbed as "Carl from Ecuador," on the kids.
The first one he comes to is Rolf, who is sitting under the bleachers and feeding the results of his latest English quiz to his goat. Eddy quickly steps in and gives him his backstory: his name is Carl, and his family just flew in from Ecuador. Upon hearing that Eddy is a foreigner as well, Rolf takes to him, wishing to share his sorrows. Eddy is then greeted with a simultaneous fortune and blight: Ed. Ed's appearance steals Rolf's attention away from "Carl," which is fortunate as Eddy doesn't have to listen to Rolf's spiel about his homeland, but Ed is looking for Eddy, and has even made fliers with Eddy's countenance on them. Eddy, not wanting to be recognized, quickly escapes from under the bleachers and walks straight into a fast-flying football.
When Eddy looks up, he hears Kevin calling him, congratulating him on the catch. Eddy comes over, surprised that Kevin would call to him, and is greeted with not the expected derision but a type of accepting respect. As a token of this respect, Kevin calls that it's time to break the new kid in, and everyone but the Eds, the Kankers, and Rolf dogpile on Eddy. Nazz introduces herself to him, and "Carl" is looking as though he'll genuinely be accepted when Ed arrives, once again bearing fliers advertising Eddy's disappearance.
None of the kids are terribly traumatized, or even mildly inconvenienced, by Eddy's departure, though. In fact, the general feeling is one of happiness, and the kids disperse for various reasons, leaving "Carl" alone with Ed and Edd. Edd asks Eddy how things are going, and Eddy reveals that he's feeling more paranoid than before, as the kids are actually acting nice. Edd explains to Eddy that this is actually natural; unlike Eddy, "Carl" has done nothing wrong and so he's accepted by the other kids rather than mistreated. Catching on, Eddy says that if this is the case, he is Carl from now on. Edd attempts to argue with him, but Eddy refuses to listen, as Carl has (according to him) the good life. Kevin then reappears and asks Eddy if he knows the two Eds. Eddy quickly fibs and says that there is no way that he'd hang with those two washouts, and the two go off to play. Edd is offended by how Eddy would so readily sell them out, while the oblivious Ed is unhappy because Eddy is missing. Edd, coming up with a plan, states to Ed that he has a feeling Eddy will be back sooner than even Eddy suspects.
Later that day, the kids are coming in from playing in the schoolyard. Kevin is telling a story about how he was able to raise his grade by giving a false compliment to the teacher. Eddy figures out when to laugh and does so, complimenting Kevin on his story before going to get a drink from the fountain. As he drinks, he looks up and sees that the graffiti has changed: the name "Eddy" has been crossed out and replaced with "Carl." Eddy then looks around and sees the kids laughing, presumably at something Kevin said. Eddy doesn't see it this way, however, and his paranoia kicks into high gear. Eddy quickly flees, much to the surprise and shock of the kids.
Eddy leaps into the lost-and-found once again and comes up with a new disguise that he dubs "Hugo." When he comes upstairs again, however, he finds that "Carl" has been crossed out and replaced with "Hugo." Agitated, Eddy rushes downstairs and creates a new persona, female this time, named Suzette. Plank senses something fishy this time, however, and after taking a look up Suzette's skirt tells Jonny what's really going on. Jonny then whispers something to Kevin, and Kevin throws a football at Suzette–a guided missile that knocks Eddy out of the dress, leaving him exposed. After some mockery, the kids vacate the hall, leaving Edd to come up to Eddy and have his turn at making fun of him. Ed also arrives, and, after hugging Eddy, reprimands him for having worried Ed sick. He then proceeds to drag Eddy outside, and for the rest of the day keeps Eddy on a short leash. Edd, still inside, looks at the graffitied wall and pulls out a sponge, revealing that he wrote the replacement alter-egos on the wall with a water soluble marker in order to teach Eddy a lesson. Edd then cleans off the alter-egos, but stares at the original graffiti, which won't come off, wondering who exactly was responsible for writing it in the first place.
As the kids were leaving school for the day, Ed told Eddy all about the new kids he met today, unaware that his friend was all 3 of them all along.
It's never revealed who wrote "Eddy is a no-neck chump" on the wall in the first place. While Edd had written the other names, he himself seemed to wonder who had written the original sentence.