আপনি should নকশা the main area that the party will be in like the bunker, I think that would be really cool. Maybe, আপনি can have it to so that they either dress like a hunter অথবা a monster, that would be fun. I don't know, that's just my thoughts.
I actually had a অতিপ্রাকৃতিক birthday party a few years ago. What we did is watched some অতিপ্রাকৃতিক episodes and we made special goodie bags that included white rock ক্যান্ডি চকোলেট (rock salt), some যেভাবে খুশী other stuff too that আপনি could see being অতিপ্রাকৃতিক related, even made the invites body ট্যাগ which was fun and I made a অতিপ্রাকৃতিক mix cd for everyone. It was a blast. And our treat was specially made কাপকেক that stand for each of the characters. I think I did a pick post on those once but I it was awhile ago. I hope this helps if আপনি had অথবা have had your party already. Sorry for being late if so