Hitch Hiker

Found this on the drivers? door of my car this morning, how did it get there?
I have never seen one in my garden before; I have however seen many of them in the grounds around the office. Yesterday I parked my car tail end into some long grass so I can only assume it slithered onto the rear of my car in Edinburgh and survived the journey to Cumbernauld. Its powers of adhesion were certainly evident when I tried to remove it.