Idk man, hands. I just like drawing hoards of hands, yo. I'm not even that good at hands, the best compliment I ever got on hands was that they were so deformed and gross-looking that they couldn't look away.
One of the grossest things I can think of is getting scratched by a human being. I have a horrible phobia of long fingernails, even well-manicured ones. So naturally fingernails are one of my favorite things to draw, in the same vein as the maggots that keep showing up in my art. I'm a fan of skeeving myself out.