I walked a bit further down and found:
This "Become Your Dream" artist has often made his mark on my neighborhood, and he occasionally breaks from the fish-with-feet to instead draw snakes, all of them admonishing passers-by to Become Your Dream. He (I do believe he is a He) becomes particularly active on garbage days, and leaves his images on discarded cardboard, tables, toilets, anything with enough surface space.
I hope some day to catch him at his craft, but suspect he might be a bit like the enigmatic Banksy (for those unfamiliar with Banksy, go right away to: http://www.banksy.co.uk/outdoors/horizontal_1.htm). There is no comparing the art of the two, of course, but they are both mysteries to me and both make me smile.