It was back in 1993, director Joel Schumacher and his friend Tim Burton, along with Lee and Janet Scott Bacthelor to work on Batman 3 for Warner Bros. Schumacher chose Two-Face as the main villain and The Batchelors picked The Riddler as the secondary villain. Schumacher knew he wanted Tommy Lee Jones for the role and he asked Robin Williams for The Riddler as The Batchelors wrote it with him in mind. When he turn it down, he found The Riddler way too intellecual, but not as comedic as The Riddler played by Frank Gorshin in the television series. So the role went to Jim Carrey and the rest is history. Here's a fanart of Williams as The Prince of Puzzlers.