Cat Girl
1957

Cat Girl may not be an out-and-out classic, but we have it to thank for giving Barbara Shelley her first starring role. Gorgeous Babs purrs her way through the film looking great, and showing far more flesh than expected for 1957. Hooray!
I don't think I'll be giving too much away if I tell you the story involves a girl who, due to an ancient lycanthropic curse, turns into a cat. And kills people. It doesn't help that she's got a history of mental illness, her husband is busy shagging her best friend, and her uncle's a nutter who abused her as a child.
We never actually see Leonora (Shelley) fully turn into a cat, but despite efforts by the filmmakers to make out that it could be her mental illness that's to blame, it's pretty obvious that there's more to it than that. The curse is at one point dismissed as "the morbid hobby of an unhinged old man," and when Leonora asks "could a woman have done this?" after wrecking her room, her doctor caringly replies: "A mentally disturbed one could have… did, in fact."
The plot doesn't make a great deal of sense (shortly after that last exchange, after showing her doctor that she's obviously crackers, he still lets her out of the asylum she's been locked up in), and everyone else seems determined to ham it up at every opportunity.
"Better she had never been born than to come back to this…" says her uncle's housekeeper.
"It was her destiny to be born a Brandt, as it is mine to die as one…" her uncle answers. He still seems pretty surprised when he does get killed, mind you.
Uncle is also responsible for this rant: "The love of darkness, the craving for warm flesh and blood… it is my legacy to you… passed on from generation to generation of our family… for 700 years!"
Leonora herself is not averse to a spot of melodrama as well, going on and on about warm blood, and, in a highlight of the film, absent mindedly telling a policeman who offers her sympathy for the death of her husband: "Why should you? I killed him. I would have ripped her apart, too!"
She also gets to casually snack on a budgie.
Cat Girl was never going to win any awards - just like pretty much every other monochrome horror of its time, it was hopelessly eclipsed by Hammer's Curse Of Frankenstein the same year. But with a central performance like Shelley's who needs art? "Let's just say it's something to do with the conquest of mind over matter…"