Jekyll and Hyde

One evening he experiments on himself and finds that his formula works. Unfortunately, his "real" self turns out to be the monster Edward Hyde. Jekyll continues his researches, spending more and more time as Hyde until this horrifying character takes over

Jekyll's fiancee and friends slowly become aware of the changes in him but are powerless to help. Jekyll himself finds it more and more difficult to keep Hyde at bay, and his initial delight soon turns to despair

When Hyde brutally murders one of the young maids, he realizes his experiment has gone too far, and he takes the only possible course of action left to him