In regards to the purple squirrel. A few years ago I was working next to a chemical storage facility, and there were stray cats around the place that were red or blue in colour, one was purple.
When I asked one of the locals about it he said that there had been some spills and the cats had got into the chemicals. Probably a similar situation here?
Pics of the red cat -->
flic.kr/p/bt4ufg and flic.kr/p/bt4ud8
Didn't get a photo of the blue or purple ones