Eric Theodore Cartman is the main character of South Park, in the cast with Kyle Broflovski, Stan Marsh, and Kenny McCormick. He is a fat obnoxious little boy, who cusses at people, disrespects his elders, hates Jews, and just acts like an annoying, irredeemable little piece of shit. He is also very fat and whenever he makes fun of someone, they insult him back, by calling him fat. He has made a few cameo appearances on Family Guy.
In the episode "Boopa-Dee Bappa-Dee", Peter tries to change the channel on an Italian TV, but ends up changing the channel on Stewie, turning him into other characters from other shows. Most of these other characters fit the archetype of a mouthy, wise-cracking, irritating little youngster in a (primarily animated) sitcom, not too different from himself. One of which is Eric Cartman from South Park.