This “Papervision” creature is quite possibly the most amazing thing I’ve seen in a long time. I kid you not that when I first got it to work, I felt like I was playing around in the future.
To get your own, just visit this page and download and print the required symbol. Then, point your webcam at the symbol and watch the creature spring to life.
It works in real time, so you can move either the camera or the symbol all around and the creature will react accordingly, and it’s even aware of depth, so you can move the symbol close to or away from the camera, and the creature will grow or shrink as if it was a real object.