Dr. Evil's most prominent feature, of course, was his head: his face resembles that of an alien, with lizardlike features and bulging eyes, not to mention his barely-sneering mouth; in addition, the entire top of his head is exposed to reveal his brain. His body is sculpted identically to Captain Action's, only colored light blue. His outfit (this was the 1960's, remember) consists of a shiny body suit, large golden medallion, and sandles.
There were two sets released: the basic boxed version which included the Dr Evil figure, grey two-piece outfit, medallion, sandals, ray gun and human mask. Later in 1968 he was issued with 'His Disguises and Weapons' - a window box set which added an oriental face mask, lab coat, thought scanner, hypnotic eye, laser ray gun, magnifying glass, ionized hypo needle and reducing ray.
According to the fictional mythology developed in DC Comics' version of Captain Action, Dr. Evil had been the father of the Captain's late wife, who had been rendered malevolent (and, presumably, disfigured) by a laboratory accident.
(Incidentally, the figure is named 'Dr. Evil,' just like the Austin Powers character. It's not 'Evel,' 'Evile,' or 'Eville,' as one often finds in toy guides and on various websites. It's Evil, already! What's so difficult about that?!)