Bookends only appear in the course Big Boo's Haunt. There are two types of Bookends. Members of the first type possess sharp teeth and disguise themselves as regular books within a bookshelf. They slide out if Mario gets close enough, open their mouth, and charge through the air at him to attack. The green books disappear if they hit anything, including Mario. Attacking them gives Mario a Blue Coin and defeats the book. The second type is only found in one room, the library, where they are found in infinite numbers. This type is smaller, never opens its mouth, and flies quickly from one shelf to the other in order to attack Mario. If Mario inputs the sequence to open the hidden door incorrectly, a Bookend will hit him instead. Getting attacked by either type of Bookend results in the loss of two life points. In the DS version both types of Bookends do the same thing to Luigi and Wario.