Creeping Flesh

First Appearance: The Creeping Flesh (1973)

So there's this Victorian scientist (Peter Cushing) who's trying to find the origin of the species man, he finds a big weird skeleton in New Guinea which he naturally brings back to his lab in England to study. While washing the skeleton he notices that putting water on it makes it grow flesh, of course. He decides to look up some  of the legends of New Guinea and obviously discovers that the skeleton is that of some super evil god monster who will destroy the world when it gets wet. Only that wasn't supposed to happen for another 3,000 years when the natives of New Guinea would have sufficient technology to fight it.
This leads the scientist to the assumption that blood from this monster is the source of evil, which means evil is a disease which can be inoculated against if you had the proper serum. So he makes the anti-evil serum and then, since his wife (who was a bit loose) went crazy and he's afraid the same thing will happen to his daughter, he injects the untested serum on his daughter. As you probably guessed this wasn't the best idea the doctor had.  Oh and the scientist's got a jerky step brother (Christopher Lee) who runs the sanitarium the scientist's wife was incarcerated in and is entering the same science competition the scientist entered. Pretty good atmospheric horror flick if you're into those Hammer style horror movies.