Steve's worst foe, the shoe goblin ardently defends shoes whenever he comes against one who is disrespectful of them. Generally, this retribution is delivered in the form of a shoeing of epic proportions. The shoe goblin is especially defensive of tiny shoes, as seen in Comic 34.
The attacks on Steve impact him psychologically so much that he has dreams about the shoe goblin, as seen in Comic 36.
The first mention of the Shoe Goblin (in Comic 11) seems to indicate that Beaver thinks he is one of Steve's imaginary friends, but this opinion seems to have changed by Comic 98, when Beaver himself acknowledges fear of the Shoe Goblin.