Be A Ninja

The Ninja Manual is only seen in "The Chamber of Frozen Blades." Jake is seen reading it at the beginning of the episode. Jake says he and Finn found it in a ditch. The book claims that through a series of listed hand gestures, you can turn your boogers into smoke bombs, but nothing more is know about it's contents.

Appearance
It is red, case-bound book. The front of the book has an image of a classic ninja with red, Japanese-like text that states "Be a Ninja". On the back are two crossing katanas (samurai swords) with a shuriken (Ninja star) in the middle.