In 1967, Sesame Street puppet creator Jim Henson used the “Wheel-Stealer” puppet for an IBM training film called Coffee Break Machine. In the sketch, called “The Computer Dinner”, the monster (with frightening eyes and fangs) devours a complex coffee making machine as it describes its different parts. When he is finished, the machine announces the monster has activated the machine’s anti-vandalism system, which contains the most powerful explosives known to man.
Two years later, Henson used a similarly-designed and equally ravenous monster for three commercials selling Munchos, a Frito-Lay potato chip. This time, the puppet was called Arnold, the Munching Monster. After the three ads were produced, Henson had the opportunity to renew the contract. He chose not to, because at that point he was working on Sesame Street — and that monster puppet was moving on to the next stage in his career. According to Frank Oz, in a later routine the then unnamed monster won a quiz show and for winning was “given the choice of $10,000 cash, a new car, a trip to Hawaii, or a cookie.” He took the cookie and from then on he was Cookie Monster.
By the way, the Cookie Monster’s real name is Sid. Really.