Blood!

This is what happens when you're too stupid to move your leg out of the way of your pedal as it swings around, and too strong for the safety of your own body.  This was the nice picture.  I could have taken a gorier one where the sock sported a lot more blood and I was dripping more copiously.  The folks at the library were too nice to comment on the guy bleeding all over his leg who came in to return and check out books.