Just remember you might have to work tighter an use a hook one size smaller in order to obtain a reasonably sized hair bow. But, I really love the RedHeart Reflective line. I ride a bicycle almost everywhere I go, and my reflective hat has saved me a time or two (No Joke).
my Ravelry store. It is for a simple crochet hair bow. This would be great for Halloween if you worked this up using the Red Heart reflective yarn.