"Um, sir? We don't have any prop swords left over for Jimmy to use in this scene and -"
"All right, just get that umbrella out of my car. It'll have to do."
When I worked at a video store we had a couple dozen of these and they are all precious gems. According to the boxes, they sold for or so a pop in '80s dollars, which strikes me as the "Make it expensive enough and we only need to sell one!"school of pricing.
-Your ninja headband
-A lot of cartwheel training
-Bright colored clothes
-An object that makes no sense for using as a weapon....unless you are a ninja