Hey! Zodiac was a very effective villian… when I was eight.
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There’s Snidely Wiplash – his schemes never succeeded – but of course, we weren’t supposed to take him seriously.
There was a recent Batman storyline where the usual group of suspects were thought of as possible instigators. One villain left unaccounted-for was the Riddler, basically because everyone considered him somewhat of a douchebag and not worth any regard. I had to agree with the writers in that sentiment.
The Riddler definitely stands out as particularly lame. A super villain whose only power is the ability to tell the heroes exactly what he and his aprtners are going to do?
He had to be a spy from the Hall of Justice who managed to infiltrate the Legion of Doom. Although how he managed to convince the rest of the Legion to let him drop clues everywhere is beyond me.
Not to mention that he stood up and fired a .50 cal machine gun from the hip! How easy can that be? He was also quite successful in his plot to destroy the commies (although not in the way he originally intended).
Nitpick: It was a .30 caliber Browning machinegun, not a .50.