You're at a Halloween party that's been hosted by your enemy and you're only there because of the free food and your costume is (costume) and (costume) mixed together so you would have something unique to wear.

As the time went on you made sure to eat everything when you got the chance just to be annoying to your enemy but everytime you went over to eat you saw the same person in the corner looking at you but you didn't know who because of their costume and it's like nobody is noticing them.