What should my pony and I be for halloween?

She flea-bitten gray and 14.3 hh. She is super smart. She is welsh/arab and she is not spooky. I don't particularly feel like dressing up but I am willing to =) She looks like a unicorn A LOT. We were thinking unicorn, but, we don't really know how to make that kind of costume. Any suggestions on that too? Thanks!!! Answers appreciated!!! =D