I doodled mine a long while ago, with it sort of becoming my logo for my music as well. The X and O represent input and output, ebbs and flows, the green represents myself- as the emerald is my birthstone, and the O was colored to represent my partners during the time I dated them. It started out as blue, to represent my (at the time) girlfriend's favorite color, then yellow, to represent my (at the time) boyfriend's color. Now, it's magenta, because it's a color I associate with isolation, and detachment.
The whole cat thing's just 'cause I'm a dumbass furry.