Zombie Possessed Demon Killer (Cool Octopus)
Zombies and devils, that is one frightening face. (For those wondering, it comes from the 2012 Hotel Transylvania ad.) The roped torso is also a nice touch to the killer theme.
Rouge et Noire (Elphangor & Edalfrey)
(The costume was submitted by Elphangor and may have been inspired by Edalfrey.) Rouge et Noire, or red and black in French, appears to be a brilliantly scarier version of the villain Black Widow.
Me and Elphangor won the contest a phb it was pretty amazing. I was first and the Elphangor was second. I got some from phb (this info belong to Fishy)