Appears in: Dr. Jekyll and Mr. Hyde (1931)
Scariest moment: Having just gulped down the magic potion, Dr. Henry Jekyll's (Fredric March) face begins contorting as his skin darkens, his teeth sharpen, and, ultimately, he turns into the repulsive Mr. Hyde.
Weakness: Jekyll's conscience, plus anything that can kill any flesh-and-blood human.

On the page, author Robert Louis Stevenson's The Strange Case of Dr. Jekyll and Mr. Hyde (1886) is a shockingly dark and imaginative tale about an English gent whose latest batch of lab-made potion allows his deepest, most evil impulses to surface in the form of an alter-ego named Mr. Hyde.

It's a story tailor-made for the film medium, with its rich characterization, and, fortunately, actor Fredric March was more than up for the challenge in the 1931 movie Dr. Jekyll and Mr. Hyde. As the latter half of the title, March consistently disturbs with his animalistic demeanor and unsightly, simian look.