Unique costume ideas are usually funny or a play on words...
This website has a list of awesome ideas...HERE
- Be an inanimate object. Like a clock, cassette tape, CD. Like in cartoons make an inanimate object come to life...
- Be a phrase. Like killing time, dress up as someone killing time, literally.
- Dress as you usually would and announce that you're a Serial Killer. They look like everybody else.
- Dress up as your best friend, etc.
There are so many ideas one can try...The only limits are your imagination.