Carl Wheezer

Carlton Ulysses "Carl" Wheezer is a bespectacled dim-witted boy and one of Jimmy's best friends. Carl and his parents have numerous allergies, at times even to things that are incapable of triggering allergic reactions. He passionately loves llamas, and his passion for them is often used as a running gag throughout the series. He is also a bit cowardly and developed a crush on Jimmy's mom, as shown throughout a multitude of episodes. 
His extreme obsession for the llama originated when his parents expanded their cable lineup and he became devoted to a show called Llama Boy The Super Hero. Since his obsession began he has gone to great lengths to express his love for them, going as far as to join a fan club called The Llama Love Society, which he likely created himself.
It is worth noting, Carl is afraid of lima beans, germs, and scary stories. He is also known to have asthma, and is very stressed about his multitude of allergies and is terrified of getting any sort of illness. Also, when he is tired, his mom makes him warm milk, rubs his tummy, and sings "nani nani nani".
He frequently shows off his vocal abilities performing improvised and poetically expressed rhymes.
== Trivia ==
* Carl is similar to Filburt from Rocko's Modern Life. both are shy and akward in contrast to their ditzy and hyperactive friend (Fliburt is the foil of Heffer while 
* In the pilot, shorts, movie, and early episodes, Carl's voice was deeper, but later on the series, his voice became more high pitched.
* In Win, Lose and Kaboom! Carl mentions that he goes to Bolbi's house for cookies, while he was voting him off.
* Carl makes a cameo in a flashback in the Planet Sheen episode, Is This Cute? when Sheen saw Doppy and saw the strong resemblance to Carl, but then disregards if after the flashback.
** Carl was going to be part of the series, but Nickelodeon executives decided to make it only about Sheen and Doppy was created.
* Carl 'hosted' Rob Paulsen's "Talkin' Toons Podcast" on July 6th, 2012. In it, he reveals many hidden details including the fact that Doppy was just him in a costume, Sheen is currently in juvie (back on Earth after returning from Zeenu), and at one point he had a crush on Cindy. This most likely might be non-canon, since none of it has been confirmed in animation or any other form of media.
* It revealed in The Incredible Shrinking Town when Carl took ventriloquist lessons. He was going to sound like Cindy, but never got the chance. However; in the episode, he did sound like Sasha and Zix.
* In Journey to the Center of Carl, It reveals that Carl eats his toys because it tastes fruity and chewy.
* When Carl's suspenders had removed in the TV series, the parts where his suspenders pulled up his pants were still in the state of being pulled up when they had removed. This was fixed in Jimmy Neutron's Nicktoon Blast, and the episode Make Room for Daddy-O but was still present in some scenes in the second season episodes Sorry, Wrong Era, Grumpy Young Men, Operation: Rescue Jet Fusion, Return of the Nanobots, Holly Jolly Jimmy, and Love Potion 976/J and his cameo in the Planet Sheen episode Is This Cute? Carl's suspenders were also present in the video game version of The Adventures of Jimmy Neutron: Attack of the Twonkies.
* Carl has asthma and has an inhaler because of it, although the inhaler appeared less as the TV Series progressed.
* He, Jimmy, and Sheen are the only main characters to appear in every episode.
* He appears in the mobile game Nickelodeon Pixel Town (only available in Singapore, Malaysia, and the Philippines). You can get him if you merge Wanda and Tooth Fairy from The Fairly OddParents in the memory center.
* His phone number is 555-2275. This can be seen on Jimmy's watch.
* Carl has spawned numerous memes, one of them being the "Are you going to finish that croissant?", Where it sounded like he said "Quasol".