It's a bit morbid, only fair to warn ya.
Friend of mine was driving to her house a few nights before Halloween last year, but a deer jumped in front of her car and she couldn't avoid it. Her and her car were fine, but the deer sadly passed away. A few days later, she came to the campus Halloween party in a deer costume with a floating halo to boot.
It sounds worse than it was; you could tell she felt bad about it, and only wanted to bring some happiness back by using the concept for Halloween. Got quite a few laughs, too.