Steve from Finkbuilt has put together a cool DIY FOG Screen, unlike the commercial models that cost tens of thousands he built his on a DIY hobbyist budget. The video shows a perfect application which is a scary Halloween evil eye.

"The effect uses rear-projection video, shined onto a screen of water vapor created by ultrasonic atomization, that is sandwiched between 2 laminar airflows, which keep the sheet of fog contained. The commercial Fog Screen that spits out this screen costs tens of thousands of dollars for the small one."