The Plague Doctor is an old Carnival mask dating back to the Black Plague. A full face version of this bird mask was worn by doctors. I have heard several theories as to why...one was that the plague was thought to be born by birds (though, in fact, it was the fleas on rats that were the carrier), the other is that doctors would keep sweet smelling stuff in the beak of the mask to make things bearable for them. Whatever the actual case was, this is a smaller version of the Plague Doctor mask with a post-apocalyptic bent to it. Hence the bio-hazard symbol on the eye, the grimey lenses, and the dented metal look. I'm sort of working on a drawing with a similar theme, but I thought it'd make a great mini-mask, too.

Edit: If you like this mask, you might be interested in the more elaborate one I did as part of a full costume this Halloween- [link]