Carlton "Carl" Ulysses Wheezer is one of the main characters in The Adventures of Jimmy Neutron: Boy Genius. He is one of Jimmy's best friends.
Carl is obsessed with llamas and has a crush on Judy. In "Carl Wheezer, Boy Genius", his crush was Elke Ekeberg, his pen pal from Sweden. Sometimes, Carl soils himself. He appears to love eating food and can eat about any kind of food, even ones that aren't edible. Carl has a very sensitive scapula and always shouts if it's hurt. He dislikes lima beans, germs and scary stories. Examples are shown in "I Dream of Jimmy" and "Sleepless in Retroville". Carl seems to be envious of Jimmy's super intelligence and all the attention he gets from girls. He also hates testing Jimmy's dangerous experiments because they constantly injure or endanger him.
Many fans aren't fond of Carl, mainly because in later episodes, he came off as very annoying with his constant whining, the jokes about his scapula and his creepy stalker-like obsession with Judy. It doesn't help that he betrayed Jimmy in one episode.
Carl had a cameo in Planet Sheen when Sheen thought, at first sight of Doppy (Carl's Planet Sheen counterpart), he was looking at Carl in the episode, "Is This Cute?" This makes Carl the only character from the original series (besides the obvious) to make any appearances on Planet Sheen.