Major spoilers in the next two pieces if you didn’t figure it out in Ch. 20. If you don’t know what “it” is, you didn’t figure it out. It was obvious to some readers, but not to others, and the readers to whom it wasn’t obvious warn you that you don’t want to look at this. Very very slightly NSFW:

http://i.imgur.com/WS5aw.jpg
http://alethiar.deviantart.com/art/Pioneer-Voldemort-163515090