Wow, that is amazing! I wouldn't just use that as a Halloween decoration... that would be in my yard all year round! (Of course, when I have my own place I intend to constantly keep it decorated for Halloween, so maybe that isn't saying much.)
By the way, I forgot to say this in my first post, but I love everyone's projects! There are so many amazing projects in this thread that I completely lost track of what I wanted to comment on, so I'll just say: you are all awesome and your projects are inspiring! Go Hogwarts!