Curse of the Demon, a black and white production from the Fifties. Surprisingly, Rotten Tomatoes had it rate in the 90s. What's cool about it is the demon. It appears out of a small cloud of smoke which gets bigger and bigger until the whole demon is there and you don't stand a chance. It's called forth by an ancient script that a professor finds. A customary formula for such genre, but the demon is worth watching it.