“In 1966, Henson drew three monsters that appeared in a General Foods commercial that featured three crunchy snack foods: Wheels, Crowns and Flutes. Each snack was represented by a different monster. The Wheel-Stealer was a short, fuzzy monster with wonky eyes and sharply pointed teeth. The Flute-Snatcher was a speed demon with a long, sharp nose and windblown hair. The Crown-Grabber was a hulk of a monster with a Boris Karloff accent and teeth that resembled giant knitting needles. These monsters had insatiable appetites for the snack foods they were named after. Each time the Muppet narrator, a human-looking fellow, fixes himself a tray of Wheels, Flutes and Crowns, they disappear before he can eat them. One by one, the monsters sneak in and zoom away with the snacks. Frustrated and peckish, the narrator warns viewers that these pesky monsters could be disguised as someone in your own home, at which point the monsters briefly turn into people and then dissolve back to monsters again.”
As it turns out, the commercial was never aired -- but all three monsters had a future in the Muppet cast. The "Crown-Grabber" was used in an Ed Sullivan Show sketch, in which he ruins a girl's beautiful day. Known from then on as the Beautiful Day Monster, he made a number of appearances on Sesame Street and The Muppet Show. The "Flute-Snatcher" turned into a background monster from The Great Santa Claus Switch and in The Muppets Take Manhattan wedding scene.
And then there's the "Wheel-Stealer", who was destined for greater things.
In 1967, Henson used the "Wheel-Stealer" puppet for an IBM training film called "The Coffee Break Machine". In the sketch, the monster devoured a complex coffee maker that explained its construction. His greed gets the better of him, however, as the machine's recording continues (within his stomach), announcing that the monster has activated its anti-vandalism program, which contains the most powerful explosives in the world. The monster promptly explodes. This sketch was also performed in October, 1967 on The Ed Sullivan Show, although it turns out that the machine itself is a bomb.
Two years later, a similar-looking monster named Arnold was used for three commercials selling Munchos, a Frito-Lay "potato crisp". 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.