"He hasn't been himself of late." -Edwina Hyde, referring to her 'brother,' Dr. Henry Jekyll.
There are quite a few films with scenarios which just make you ask "WTF?!?" Some, like North(1994), deservedly disappear from cinemas as fast as they arrive. Others, like Twins(1988), turn out to be surprisingly watchable. What made the latter work was mainly the engaging performances of Arnold Schwarzenegger and Danny DeVito playing the most unlikely of twin brothers. Having Ivan Reitman, who had already directed gems such as Ghostbusters (1984), behind the camera was another plus.
Another good film with an outrageous premise is this take on Robert Louis Stevenson's classic story The Strange Case of Dr. Jekyll and Mr. Hyde. Even those who have never read the book know the basics: a kind doctor, one Henry Jekyll, ingests a self-made potion he theorizes will segregate the good and evil known to reside in each man. The potion, however, turns him into Edward Hyde, an individual uninhibited by ethics or conscience. The transformations between the two become sporadic until Jekyll, horrified to learn of the acts he committed as Hyde, begins to desperately find ways to kill Hyde forever. The book has been adapted for the screen numerous times over the decades.
One of the best was the 1920 adaptation with John Barrymore playing both roles (and famously distorting his handsome features to play Hyde). Eleven years later, Fredich March would win an Oscar for playing the dual roles in another film version. One common trap many of the Jekyll films fall into is the decision to have Mr. Hyde appear animalistic or wolf man-esque. Anyone who has read Stevenson's story will tell you that there is no such description of Hyde present. Hyde, while certainly ruthless, reflects the nature of humanity as much as Jekyll does.
This is why the story and its two main characters have become such a famous example of humanity's inner struggle of good and evil. Not surprisingly, the duality of the title characters were also influential in the creation of characters such as the Wolf Man, the Incredible Hulk and the Batman villain Two-Face.
The film version which was probably closest to Stevenson's story was I, Monster (1971), in which Christopher Lee plays the good doctor and his vicious counterpart. The 'Hyde' makeup on Lee is not over the top as it is in other versions and he expertly plays the differences and similarities of both characters. One interesting deviation, though, was that Lee played Dr. Marlowe and Mr. Blake, while all the other characters had the same names as in the story.
Dr. Jekyll and Sister Hyde is Hammer Films's take on the classic story with a unique twist: the doctor turns into a beautiful but vicious woman. Reportedly, screenwriter Brian Clemens came up with the idea over lunch with director Roy Ward Baker. Baker initially thought Clemens was joking until Clemens wrote the script that very night. The good doctor (Ralph Bates) attempts to create the elixir of life with female hormones, which he obtains, amusingly enough, from cadavers given to him by two fellows named Burke and Hare (real-life serial killers who terrorized Scotland in the 1820s). When he takes the potion, he unexpectedly becomes the beautiful Edwina Hyde (Martine Beswick), who passes herself off as Jekyll's widowed sister. Naturally, it isn't long before Hyde begins to take over and, following the lynching of Burke and Hare, commits murders whom the public attributes to, yes, Jack the Ripper. One big plus of this film is the uncanny resemblance Bates & Beswick have to each other. Both are very good at playing roles which must have been a challenge. Needless to say, the film ends on the same note the story does.