What is the one thing, that if you had to touch with your bare hands, would send you over the edge?

As the title says... What would it be that would give you the heebie-jeebies and make your skin crawl?

I've touched a lot of stuff in my seventy years. Not all of it pleasant. I've worked in ERs, I'm a parent. Yep, lots of icky stuff! I don't know that I have an answer to the question myself.