The characters of Sam and Max were created in Purcell's youth; Purcell's younger brother Dave originally came up with several comics around the idea of a dog and rabbit detective duo. Dave would often leave unfinished comics around the house. Deliberately making the characters mix up each other's names, shoot at each other and mock the way in which they had been drawn, Steve, in a case of sibling rivalry, would sometimes finish the stories in parodies of their original form. This developed from Steve mocking his brother's to the creation of his own stories with the characters. In the late 1970s, Dave Purcell gave Steve the rights to the characters; he signed them over in a contract on Steve's birthday and allowed him to develop the characters in his own way. Purcell believes that his younger brother has recovered and forgiven him from their earlier years. Having kept one as a pet in his youth, Purcell has an interest in rats, which are commonly featured in his artistic work.
