Saw this on goaste_request and thought it was so cool. A Canker Worm is another name for an Inchworm, the larvae of a Geometridae moth. They are pests and their cocoon building can get out of hand as you can see: I wish I knew how long those bikes have been there. SOURCE, and even more Pics: http://user.it.uu.se/~svens/larverna/normal.html read more