Halloween and geek conventions have one awesome thing in common: They give women an excuse to wear outfits that their own sense of modesty and dignity would otherwise never allow them to leave the house in.
Therefore, the costume industry struggles mightily to come up with a "sexy" version of every single costume ever made. The results cover the spectrum from laughable to terrifying.
Wait, is she supposed to be a guitar? Or just a fan of guitars? A guitar advocate? In any case, the neck of the instrument is jammed through her skull, and it's going to take forever to get that thing back in tune.