Ratbert is a regular character from the Dilbertcomic strip. He was not originally intended to be a regular, instead being part of a series of strips featuring a lab scientist's cruel experiments (Ratbert's name at this stage was XP-39C²). Ratbert soon realized that he was the subject of a hideous macaroni and cheese experiment (the scientist made him eat huge amounts of it and writes in his notebook that it causes paranoia in rats) and escaped, eventually finding a refuge in Dilbert's house. He was not initially accepted by the residents, especially Dilbert, who was highly prejudiced against rats. However, he finally allowed Ratbert to become a permanent member of the household.
Ratbert chose his name through a discussion with Dogbert. Dogbert suggested names such as 'Rodney the Rodent' and 'Vernon the Vermin'. XP-39C² suggested the name 'Bill the Rat' before finally settling on 'Ratbert'.
As a simple rat, and having been specially bred to be susceptible to peer pressure, Ratbert is very gullible and innocent, although optimistic. Sometimes his actions can become quite annoying, such as doing "rat dances". Like Dogbert, he has made inroads into business, once working as an intern, a concierge, a consultant (with an "external brain-pack" tied to his torso, which was actually a slab of liver) and vice-president of marketing (for which he was hired on the basis of his week in a dumpster at Procter & Gamble). He also became CEO after a series of strips that involved the previous CEO jumping into a volcano and the first replacement (a vampire) burning up due to daylight. Ratbert was fired for varnishing employees for use as office furniture. He received a severance package of $100 million, the corporate jet, perpetual benefits and a salary of $1 million per year.
Ratbert's biggest ambition in life is to become loved and accepted. He tries to impress those he considers his friends on various occasions, and nearly always fails miserably. Just like Dogbert protects Dilbert on numerous occasions despite his contempt for him, so do Ratbert's friends and family. Ratbert is friendly with Bob the Dinosaur, and is also good friends with the garbage man, who tries—and fails—to enlighten Ratbert on the complexities of the universe.