Horror films that don’t explain what the villain is?

I often find that a horror villain starts out the scariest because you don’t know much about it. But by the end, the movie has to resolve itself so you often are told the villains (a “villain” being a person, supernatural force, whatever) motivations or identity.

For example I recently watched Longlegs, which I really liked, but by the end when the whole Longlegs mystery is explained etc, I found it wasn’t as scary. Still an awesome film and I don’t think it should end any differently really.

Some films top of mind that don’t explain the villain by the ending is The Shining and some Lynch stuff, like Twin Peaks. I’m sure there are others I’m forgetting. What about you?