RTA Guide/Secret of the Haunted Books
Secret of the Haunted Books is the third mission of Big Boo's Haunt.
After entering the mansion, hold slightly left to turn Mario, but don't hold all the way left until you have jump kicked. If you don't do this, you will be too close to the wall when you double jump and won't get enough height from the wallkick.
Fast Sideflip Wallkick