(http://img262.imageshack.us/img262/3027/green9qq.jpg)
The green thing about midway up the cake is new and seems to be growing. I'm assuming it's mold and have isolated it from the others. This is P.C. Z strain. Any chance that this is something other than mold? The other cakes it was with do not seem to have the same affliction.
Seems to be mold, yes. In addition to isolate the cake, cut the infected part out.