A lot of the streets i visit have a gnome by the signpost. It seems the layering of the two is off, as the gnome is often *under* the metal rock instead of in front of it (so I don't see anything but maybe its pointy hat). When I walk past and the gnome does his "someone is passing" dance, he pops out in front of the rock. Attack Gnome! Assuming this is a bug :)