3. Mr. Freeze (Batman & Robin)
Out of all the things wrong with Joel Schumacher's Batman & Robin, Arnold Schwarzenegger as the villainous Mr. Freeze is one of the most offensive. Arnie hammed up the role, but when he was being given lines like "What killed the dinosaurs? The Ice Age!" there wasn't a whole lot he could have done to make it work.
It took an eleven-man team up to six hours to help the Terminator star get into his costume and apply his make-up, although Arnie is said to have had a bunch of handlers giving him massages to make the process a little more comfortable. He also had to shave his head and wear special blue contact lenses for most of his scenes.
However, the worst part of all was the way the costume designers decided to make his mouth glow. Little LED lights were fitted around his teeth for a rather pointless special effect that turned out to have a dangerous side effect. The batteries used to power the lights actually started leaking acid onto the star's tongue. Schwarzenegger was understandably pretty upset about this and a little balloon had to be used to act as a barrier between the battery and Arnie's gums.