Jacob’s Ladder
I distinctly remember a nightmare where I was in a classroom with no windows that suddenly sealed itself off from any and all outside people. A group of scientists outside used a machine to register the heat signatures in our room to see what was going on. It turns out that it was filled with ghosts and demonic shapes, all looming over each student. This nightmare came a few hours after I watched Jacob’s Ladder so I’m definitely blaming that film for this.