Early Calvin and Hobbes

Marvin was an early concept for Calvin. He was just like Calvin except that he had much longer, shaggier hair. The name was eventually changed to Calvin, then later Bill Watterson removed the long hair as he felt it looked ridiculous for such long hair to be covering the boy's eyes.

Few strips exist with Marvin. One was where he's in his Spaceman Spiff outfit in class and gets sent to the headmaster. A second strip had Marvin eating dinner with his parents and requesting him to take some to Hobbes. Marvin's father (an older looking version of the later design Calvin's father) is unaware of Hobbes, to which Calvin's mother (Also a more older looking version of Calvin's mother) explains that Hobbes is an imaginary friend and chalks up Marvin's request to desiring extra helpings. Marvin then brings the food to Hobbes, who said the request for wine was denied. A third strip that did get completely revamped was where Marvin sneaks out of his house at three in the morning, going to a nearby payphone to ask his father "Do you know where I am?".

These strips are shown in the book, "Exploring Calvin and Hobbes: An Exhibition Catalogue"

Bill Watterson eventually ditched the Marvin name after (2?) strips but kept the longer hair design temporarily, before removing it after (3?) strips:

Marvin Comic Strips

Calvin with Shaggy Comic Strips