This isn't exactly a trauma, but it's driving me mad that I can't remember what the film is.
â€˜70s-era (or maybe, maybe very early '80s) horror film.
The image that I remember is of a woman being stalked (possibly) and then dragged off (almost certainly) by an unseen or mostly implied monster, possibly into an air vent.
The part that sticks with me is she's using a camera with a flash (electronic, I think), to stun or slow down the monster; every time she flashes it, it stops dragging her.
Anyone recognize it? I've never seen the flash gimmick anywhere else, and I think it's unique to that film.
(The worst part is, I *knew* the name once, having found the description in one of the old print books that listed movies… but have since forgotten it. The film was, if I recall, supposedly fairly influential [or its producer was] in underground horror…)