The Book On Bad

The Book On Bad is a supposed collectible, similar to the Ghoul Medal in nature, in Super Mario 64. It is supposedly a book written by Bowser and his army, presumably about being evil. It was first mentioned by a Toad in this dialogue:

"Wow! You already recovered that many Stars? Way to go, Mario! I’ll bet you’ll have us out of here in no time! Be careful, though. Bowser and his band wrote the book on “bad.” Take my advice: When you need to recover from injuries, collect coins. Yellow Coins refill one piece of the Power Meter, Red Coins refill two pieces, and Blue Coins refill five. To make Blue Coins appear, pound on Blue Coin Blocks. Also, if you fall from high places, you’ll minimize damage if you Pound the Ground as you land."

It is believed this dialogue may be a reference to the collectible, though similarly to the Ghoul Medal, some say this is just figurative speech, simply meaning that Bowser is very evil.

Some personalized copies supposedly contain The Book On Bad, usually as a book that can be read by interacting with a bookshelf found somewhere in the game. It usually describes methods on how to be evil, functions as a diary written by Bowser. This version of the Book On Bad has also reported it contains hints to various stars throughout the game. Other people claim that The Book On Bad is a collectible, usually dropped by Bowser, though what the Book On Bad does upon being collected is inconsistent.