My sister used to throw origami shuriken at me during church. This continued until the day she made me bleed and then missed with her second shot to hit my mom in the face. We no longer underestimate origami.
But it is embarassing to be bleeding from a paper ninja star to the face. or the neck. or the arm. Dying is a little less embarassing. and you see knives coming most of the time and you know that a knife is dangerous. you never suspect the origami ninja star.