Possibly I am the only person on the planet who didn't know that Homer Simpson's dog is a greyhound. The dog was introduced in the first episode of the show, the 1989 Christmas special "Simpsons Roasting on an Open Fire", in which his owner abandons him for finishing last in a greyhound race. Homer Simpson and Bart, who are at the race track in the hope of winning some money for Christmas presents, see this and decide to adopt the dog.
Here is the real Santa's Little Helper, compared to which mine is a poor imitation obviously. Created by and © Matt Groening