While Richard Gere is more likely to fall prey to the "hooker with a heart of gold" Superman's bane is the cyborg with a heart of kryptonite known as Metallo. Although a couple of characters with the name Metallo appeared earlier, the modern Metallo first appeared in 1959 in Action Comics #252. It is this version of the character that has been inducted into the lineup of the upcoming JL:Doom's Legion.
The live-action Adventures of Superboy TV series episode Metallo, pitted The Boy of Steel against the Steel Man in for the first time onscreen in 1989, some 40 years after his comic book debut. Although he looked more like a suicide bomber than a cyborg, Metallo would do his best to be the last man standing.
In 1995, Metallo returned to live action TV in an episode again titled Metallo, this time during the Lois and Clark: The New Adventures of Superman series.
Metallo would finally be animated for a series of appearances on Superman: The Animated Series beginning in 1996. This version of the villain was presented with a tragic twist that the same cyborg abilities that gave him strength robbed him of his ability to feel. Metallo returned for both Justice League and Justice League Unlimited in more of a goon capacity.
On the animated The Batman series, Metallo would square off against the combined efforts of Superman and Batman in the 5th season premier, The Batman / Superman Story (interestingly voiced by an actor named Lex Lang).
For 2009's Superman / Batman: Public Enemies, Metallo adopted a Terminator inspired ability to morph his shape. In the movie, the murder of Metallo was used to frame Superman, making him Public Enemy #1.
Later in 2009, the Steel Man would appear on Smallville. Not to be outdone by previous live-action appearances, this episode was also titled simply Metallo.
An incarcerated Metallo was briefly seen lifting weights during Clark's prison visit to Lex in 2011's All Star Superman.
Also in 2011, Metallo made another cameo appearance, this time as one of the many villains showcased in Batman: The Brave and the Bold's Battle of the Superheroes! The retro design of the villain for this appearance heralded back to the Golden Age along with many of the reverential references made throughout the episode.
Metallo will return in Justice League: Doom. What is not yet clear is who is chief adversary will be in the film. As of now, it appears that each member of the Legion of Doom will face off with a Justice League Member. While most of the match-ups are obvious, it seems as though Superman may face Vandal Savage leaving the cybernetic Metallo to face off with Cyborg in a battle of the borgs. Sounds compelling!