Wikisimpsons - The Simpsons Wiki
Üter is a German boy with his huge passion for eating unhealthy food, especially candy, and can often be seen alone eating sweets, both at school and on the school bus. His obesity also had been a running gag in The Simpsons. As such, he was whipped by a wet towel by Homer Simpson for fun, thinking he had bosoms. Üter was once caught and attacked by pursuing soldiers when he was unable to catch up to the school bus where the other students caught up.
Üter is also proven to be friendly as he offered to share candy with Bart one time. In the future as an adult, a healthy Üter also donated a digestive tract to an ill Bart as he was a loyal customer to the product Bart was selling, fish logs, and ate nothing but them since then despite that they eventually became no longer profitable.
Despite his physique, Üter used to be a player of the Kwik-E-Mart Gougers Peewee Hockey League Team. He also enjoys flirting with Lisa Simpson and sometimes tries to befriend Bart. He enjoys watching German football. He also seemed to be an enthusiast towards science fiction, as he was seen attending the Bi-Monthly-Science-Fiction-Convention.
Üter once got left behind on the American Civil War field trip and subsequently went missing. He attacked by civil war re-enactors while Principal Skinner thanked his precious permission slips. His parents demanded Skinner to inform them of their missing son's whereabouts. However, he has since reappeared. He was once seen stuck in a cobweb in the school air vents, to no avail. Üter then reappeared some time afterwards.
Üter has two parents, and an uncle who is the a proud owner of a bubblegum-factory in Düsseldorf (respectively Basel in the German version).
 Behind the Laughter
Üter is most likely based on Augustus Gloop, the gluttonous German boy from the book Charlie and the Chocolate Factory by Roald Dahl and its 1971 film adaptation Willy Wonka & the Chocolate Factory; which is rather ironic, since Üter once made a chocolate diorama of the book. His favourite catchphrase is "don't make me run; I'm full of chocolate!".
Contrary to the common English assumption that Üter is a Swiss name, it is probably a misconstruction of the common German name Günther. In the German version of the show, Üter is named Uter and is an exchange student from Switzerland with a thick Swiss-German accent.
At one point, when Lisa was discovered to have a crush on Nelson Muntz, with the other children taunting Lisa for it, Üter denied the claim, which caused the students to pick on Üter instead, claiming Üter had a crush on Milhouse.