So this is a spin off thread of something posted in the movies section.
We had a similar thread to this a long time ago called Disturbing Books... Grotesque and Disturbing are slightly different though IMO.
So I just finished reading Off Season by Jack Ketchum a day or two ago. And this book is perfect for Grotesque. But the thing is it's a great book. Everything in it is there to convey an emotion. The book wouldn't be the same without it. I think that the violence and gore is totally necessary in that book. And it's better for it.
Another great book by him is The Girl Next Door. The violence is so disturbing that I cringed at some parts and had to force myself to finish. But the story relied on these parts. Without them it wouldn't be the same.
I've heard a lot of people mention The End of Alice by A.M. Homes. But I just couldn't get into it. I made it maybe a few pages but it was just too boring. I'm sure I'll give it another shot eventually.
So - what are some really grotesque books?