This one was for another coursemate's birthday party.
Thinking about it, this was actually my second Harry Potter themed party. The first was when I convinced my brother to have it as the theme for his 12th (I think) b-day. It was sometime between the 4th and 5th book came out. I was Rita Skeeter.
Following the trend of choosing strong, powerful and nasty female characters with an original look, I went as Bellatrix. And fortunately I have a flatmate with a ton of sexy goth clothes, so I had no problem finding a costume. (The other guests were Harry, Draco, Dumbledore, Luna, Mrs Norris and (Sexy) Dobby. Good times.)
Pictures from weheartit.com