Calm down. is neither going to bite you, nor to harm you with those - in all probability poisened - steel needles on her bra.
If you keep the distance that is!
And why shouldn't you? It's not that you approach people who dress like that in your everyday life, do you?
Nope, you keep your distance. Why should you act differently with Miss Lavigne who apparently tries out Hallloween costumes early this year.