Rafael Rivera (a.k.a. DARAF) provided some of the key art for Purgatory Comics - including all of the Ace Amoeba art used in the movie, early cartoon art of the characters, and the current web site banner. Now he has a brand new hardcover book available to purchase filled entirely with his original art work.
It's called Jab, Jab, Whammo!?! The Art of Rafael Rivera A.K.A. Daraf (cover above). In it you'll see his celebrity caricatures, sci-fi sketches, and much more. It's hard cover with a dust jacket and only $45. You can preview it and purchase it right here.