Bookend

Bookends are large living books in Super Mario 64 and Super Mario 64 DS. Their name is taken from "," a shelving accessory used to keep a row of books upright.

Super Mario 64 / Super Mario 64 DS
Bookends appear only 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 mouths, 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 destroys the books. The second type is found in only 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 losing two wedges of health. In the DS version, both types of Bookends do the same thing to Luigi and Wario.

Mario Party 8
Bookends also appear in Mario Party 8 in King Boo's Haunted Hideaway. They hover around in the rooms instead of lunging at players.