White mucous substance forming around iron paper clip during electrolysis

I'm using a graphite cathode and an iron paper-clip anode, in a saltwater solution, basically to produce rust. 


I've done this before with no complications, but this time I noticed a white, mucous material forming around the paperclip, quite late into the process.
I had eaten about half-way through the clip when I started noticing the cloudy white stuff. That suggests that whatever is producing it, is at the core of the clip.


If I try to move it, the mucus immediately detaches and sinks to the bottom of the jar, where it stays above the iron hydroxide.
Everything else seems to be in order, colour-wise.


Another thing is, if I shake the mucus off, the paperclip starts off clear, before turning black again, as it should be.


Does anyone have a clue of what this might be?
I know zinc oxide is white, but I'm pretty sure zinc and iron don't mix.


I've turned the power off, just in case it's something I -really- don't want to handle without protection.


