Found a Canadian photographer who... is aparently quite popular in the art circles around here.http://www.theenchantedforest.ca/second-page.htm
Aparently his technique (recently)
"This year my photographic work is organic in nature. I develop a fungus growth on the emulsion side of the slide. In 3-4 months the fungus destroys the colours in the original slide to create a spontaneous combustion of chaos."
though you might be interested.
/me goes to adobe.com to request the addition of a fungus button in the effects menu