Joe is an anthropomorphic dog.
Joe was a dognose whose mother had always warned him not to "get mixed up with crooks". At some point, however, Joe became acquainted with Scottish crook Chisel McSue, and, in 1953, even suggested him an idea to get his greedy hands on Scrooge McDuck's fortune. However, as soon as he had executed the plan with Joe's help, McSue decided that he would be safer if there were "no surviving witnesses" to his attempted murder of Scrooge and his nephews, and consequently tried to kill Joe. Joe escaped and decided to "be a square" from then on.
Behind the scenes
Joe only appeared in 1953 in The Horseradish Story.