Saw The Testiment of Dr. Mabuse from Netflix the other day. Interesting film for its time (1933) dealing with an incorporeal evil that shifts bodies, but always has as its goal the destruction of society (and the world at large), through terrorism, anarchy and subterfuge. This evil genius, and here we use genius in the sense that it is a spirit, incarnate or not, plots and ferments his strategy of crime but uses henchmen to actually perform these anarchic works. He controls his henchmen through conditioning, a code of omerta (each are sworn to secrecy and make a pledge of loyalty), and a species of telepathic hypnosis.
The Dr. Mabuse figure is a cross between Svengali and Charles Manson, a cultish leader who through personal magnetism is able to control others' minds and compromise their free will. Is there a specific fear of being possessed? There certainly is a fear of insanity, but is there a specific fear of being inhabited by a foreign force, of losing one's self-control to the control of another? If so, that's the fear the Dr. Mabuse stories exploit.
The body-hopping spirit of Dr. Mabuse may not be unique, but it is unsettling. It's still unsetting to audiences today. The theme brings to mind the theme of David Lynch's Twin Peaks, wherein the evil genius/spirit "Bob" takes control of Leland Palmer and forces Palmer to commit acts of murder, including that of his own daughter, Laura. As Twin Peaks was extremely derivative, it's not incredible that Dr. Mabuse figured as a direct inspiration.
Dr. Mabuse is primarily a German boogeyman. Fritz Lang directed three films that included meditations on the Doctor. The most poigniant being The Testiment of Dr. Mabuse, wherein Mabuse is an idiot, senile, catatonic, except for his automatic writing, in which he fills page after page with details for criminal enterprises dedicated to the destruction of society. For example, he counterfeits money not to use its value, but to cause inflation and devalue all money.
In The Testiment, Mabuse is referred to as "the Man Behind The Curtain" which echoes the wonderful line in The Wizard of Oz, "Pay no attention to the man behind the curtain." He gives issues orders from behind a translucent curtain hung across a filthy tenement room. All his henchmen can see is a shadowy figure and a gravely voice. Once the curtain is stripped away, the figure is revealed to be cardboard, and an intercom has been responsible for the voice. The real evil is elswhere, ephemeral, elusive. Perhaps within.