Wall Walker

At a museum we went to when I was younger, one room had an enormous elephant head on the wall, which you couldn't see until you were all the way into the room. It had a wee bit of a Yikes! factor the first time you saw it, because you turned your head and there it loomed.

That place ain't got nothing on an H.R. Giger exhibit at a museum in Spain:

The original picture may be found here, and an English-language news item about the exhibit here.