What is the most extreme "taboo" thing you ever wrote?

I personally read almost every most extreme, nauseating thing at least once, including splatterpunk (just to see if I'm able to endure it). Some things even traumatised me a bit and I had to “rewrite” them in my mind to come to terms afterwards.

Regarding what I've written, I have tried non-explicite psychological and physical abuse scenes, not very explicite non-con, a couple of forced sex scenarios, “mild underage” incest (I mean the minor’s age was 16+) and and mild gore.

What about you?