What, For the Love of God, Is This Gross Thing?

I'll give you a hint: It came straight from a human mouth.
It's used dental floss, photographed by Steve Gschmeissner. I don't know what the hell is that purple stuff and I don't want to know. It's one is a series of photos in a Daily Mail article showing everyday objects under Scanning Electronic Microscopes. Here's another fascinating one, of a needle and a thread.

Now what I expected. It's weirdly unsettling how everything seems so brittle and disorganized at this scale.