Art.

An artist in Ontario started putting these up around town. In his own words: "It is supposed to be a comment on public spaces being routinely used for advertising (billboards, etc) but not for art. It is to bring a smile to people's faces, to get them to connect with their neighbours, to bring colour into an otherwise grey urban landscape."

The same artist has been known to wedge "bat-a-rangs" into walls and telephone poles as "evidence."

This installation was mimicked worldwide, until it reached the U.S., where the bomb squad was called in and charges were pressed against two girls in Ohio (read more here).