Suggest me a scary, most terrifying book youve ever read

Back in high school, i used to read this book called Mr Midnight, its a scary book for young lads like i was back then. Now that i grew out of it, i want to learn more about other scary ones. That could scare even the adults.

I have heard of The House of Leaves and The Yellow King(i think thats the name of the book?) but i want to know more other books that i havent known yet