Who is the greatest super-villain of all time? Luthor? Doctor Doom? Darkseid? Despicably evil as they are they have all been defeated. Ladies and gentlemen I give you a villain who retired undefeated with no ties: THE COMPOSITE SUPERMAN.
I am only talking about the Joe Meach Silver Age version who kicked Superman's and Batman's ass both times he faced them in World's Finest 142 & 168. Supes and Bats only survived because of Compy losing his powers just before he turned out the lights on them for good. Meach died in a heroic act of self sacrifice so he was never to return to take them on again. I am not interested in the reworkings of the character after World's Finest 142 and WF 168.
Now this story absolutely thrilled me as a child. Compy's appearance was both very cool and macabre at the same time. My favorite artist Curt Swan was fantastic at making super villains look frighteningly realistic. An ordinary janitor named Joe Meach not only acquires Superman's powers but all the powers of the Legion of Super-Heroes. He uses Chameleon Boy's power into changing himself to look like a half Superman half Batman demon with a green face.
Meach is a janitor in the Superman museum where life like Legionnaire statuettes are displayed. Very life like because each statuette was created by making an exact duplicate of each legionnaire that included his/her own individual powers. A lightning bolt strikes the statuettes and also the nearby Joe Meach who is sweeping up. A curious thing about the Silver Age is that people never close their windows during a lightning storm. Meach is then imbued with powers and an evil personality.
Like all good super-villains Compy has to toy with Batman and Superman before he destroys them just long enough until it's too late. Of course if he knocks them off in the first couple of pages there's about 14 empty pages of story, right?