Ideas for caption welcome...

I was walking to tube station this morning and was confused by this sight. As I walked up I could only see part of the arm sticking out - this is the view looking back. Other commuters didn't pause to look, did they think it was normal or did they not see it?

Sometimes blip is not about art or family or friends but instead (or also?) about the bizarreness of life.
I'll try to make more time tomorrow for a proper shot. Too zonked tonight so phone shot will do.