The lace ship.
This is some sort of dust that landed on my sample before etching - I do try to clean dust off, but I don’t get everything removed. This particular sample had a few of these airy, lacy dust particles - I’m not sure what they are made of. A typical skin cell is about 30um in diameter, so this is much smaller than even a single one of those. I was particularly unhappy to see this one, since it landed on one of my structures, and cast a shadow over it during etching.