Art by Maxwell Atoms.
If you like Billy and Mandy, be sure to watch the spinoff special "Underfist" this Sunday night at 7pm.
It was a real labor of love by Maxwell Atoms. If you look hard enough, you can see his sweat in it. There's even a B&M marathon leading up to it featuring all the Underfist heroes: Fred Fredburger, General Skarr, Hoss Delgado, Jeff the Spider, and Irwin.
Visit Maxwell Atoms' blog for more info.