There is no writing in Holy Scripture that instructs you to "scare of evil spirits" by wearing a costume.

Halloween is 100% a demonic inspired evil celebration.
---------------------- -----------------------------

When you wear a Costume, you are attempting to take on a different identity.

When you do this, you open the door to demons into your life.
----------------------------------------

So let October 31st be just that. Another day.
and Ignore the rest of the world...if you can teach others to the error of celebrating the demonic Halloween then do so.