Slimy Purple People Eater

Having made a mental note of the whereabouts of the purple 'gunge' I saw on a felled tree yesterday at County Hall (which would have been my blip if I hadn't found that almost pristine Blewitt) I managed to locate it again quite quickly today.
If it wasn't such a lovely colour (and purple IS my favourite colour of all) it'd look rather yukky - it does remind me somewhat of an alien life-form from a sci-fi movie. I can just imagine it expanding to huge propotions and taking over the planet!
Yes, I DO have a music link here - but for once I'm not going to put a proper link as I've never been a great Beatles fan (give me the Stones any day! lol)