Sometimes the scariest thing is the face behind the mask. Reddit user hpierce snapped this clockword android, from the Tenth Doctor episode "The Girl in the Fireplace," which has escaped 18th century Versailles and invaded Boston for PAX East. [reddit]
Edit: Clara Kim, the creator of this wonderful costume, emailed me a link to her build photos. Check it out so you can build a clockwork droid of your own.