Ok, I admit I've never seen this sort of thing before.
My thought is that if its just a chemical reaction to the yeast, it's harmless. If it's 'spreading' that's a different story.
But why take any chance. Not to be close minded or Medieval, but... 'anything that is new is bad and thus must be exiled'.
I say get a siphon in there and vacuum that sucker out. Keep it and examine it if you want, but remove it from the batch.