Throwing knives

Throwing Knives are an unpopular weapon used in the land of Ooo. They can be used by throwing them at a target. They training used to train on how to use them takes a very long time. Finn, Jake and the Ice King are the only people who have trained and know how to use them.

Finn used them in the episode 'The Chamber of Frozen Blades' when he was fighting against the Ice King, trying to "Save a princess".